diff --git a/achievement.cpp b/achievement.cpp
index 1770fc56..8699ca02 100644
--- a/achievement.cpp
+++ b/achievement.cpp
@@ -112,6 +112,7 @@ EX bool wrongMode(char flags) {
   if(flags != rg::special_geometry && flags != rg::special_geometry_nicewalls) {
     if(!BITRUNCATED) return true;
     if(geometry != gNormal) return true;
+    if(disksize) return true;
     }
 
   if(shmup::on != (flags == rg::shmup || flags == rg::racing)) return true;
@@ -225,10 +226,10 @@ EX void achievement_collection2(eItem it, int q) {
   if(randomPatternsMode) return;
   LATE( achievement_collection2(it, q); )
 
-  if(it == itTreat && q == 50 && (geometry == gSphere || geometry == gElliptic) && BITRUNCATED) 
+  if(it == itTreat && q == 50 && (geometry == gSphere || geometry == gElliptic) && BITRUNCATED && !disksize)
     achievement_gain("HALLOWEEN1", rg::special_geometry);
 
-  if(it == itTreat && q == 100 && (geometry == gSphere || geometry == gElliptic) && BITRUNCATED) 
+  if(it == itTreat && q == 100 && (geometry == gSphere || geometry == gElliptic) && BITRUNCATED && !disksize)
     achievement_gain("HALLOWEEN2", rg::special_geometry);
 
   if(q == 1) {
@@ -309,12 +310,12 @@ EX void achievement_collection2(eItem it, int q) {
   // 32
   if(it == itHolyGrail) {
     if(q == 1) achievement_gain("GRAIL2");
-    if(PURE && geometry == gNormal)
+    if(PURE && geometry == gNormal && !disksize)
       achievement_gain("GRAILH", rg::special_geometry_nicewalls);
     #if CAP_CRYSTAL
-    if(PURE && cryst && ginf[gCrystal].sides == 8 && ginf[gCrystal].vertex == 4 && !crystal::used_compass_inside)
+    if(PURE && cryst && ginf[gCrystal].sides == 8 && ginf[gCrystal].vertex == 4 && !crystal::used_compass_inside && !disksize)
       achievement_gain("GRAIL4D", rg::special_geometry);
-    if(BITRUNCATED && cryst && ginf[gCrystal].sides == 8 && ginf[gCrystal].vertex == 3 && !crystal::used_compass_inside)
+    if(BITRUNCATED && cryst && ginf[gCrystal].sides == 8 && ginf[gCrystal].vertex == 3 && !crystal::used_compass_inside && !disksize)
       achievement_gain("GRAIL4D2", rg::special_geometry);
     #endif
     if(q == 3) achievement_gain("GRAIL3");
@@ -599,7 +600,7 @@ EX void achievement_count(const string& s, int current, int prev) {
     achievement_gain("LIGHTNING2");
   if(s == "LIGHTNING" && current-prev >= 10)
     achievement_gain("LIGHTNING3");
-  if(s == "MIRAGE" && current >= 35 && geometry == gEuclid)
+  if(s == "MIRAGE" && current >= 35 && geometry == gEuclid && !disksize)
     achievement_gain("MIRAGE", rg::special_geometry);
   if(s == "ORB" && current >= 10)
     achievement_gain("ORB3");
@@ -633,6 +634,7 @@ EX void achievement_score(int cat, int number) {
   if(cheater) return;
   if(casual) return;
   LATE( achievement_score(cat, number); )
+  if(disksize) return;
   if(cat == LB_HALLOWEEN) {
     if(geometry != gSphere && geometry != gElliptic)
       return;
@@ -943,7 +945,7 @@ EX string get_rich_presence_text() {
     return "Guided Tour";
 
   string res;
-  if(geometry != gNormal || !BITRUNCATED) 
+  if(geometry != gNormal || !BITRUNCATED || disksize)
     res = res + full_geometry_name() + " ";
   
   if(land_structure != default_land_structure()) res += land_structure_name(false) + " ";
diff --git a/arbitrile.cpp b/arbitrile.cpp
index 43bb0b40..8b4356cb 100644
--- a/arbitrile.cpp
+++ b/arbitrile.cpp
@@ -659,21 +659,21 @@ EX void load(const string& fname, bool load_as_slided IS(false), bool keep_slide
       ep.force_eat(")");
       ginf[gArbitrary].g = curv > 0 ? giSphere2 : curv < 0 ? giHyperb2 : giEuclid2;
       ginf[gArbitrary].sides = 7;
-      set_flag(ginf[gArbitrary].flags, qBOUNDED, curv > 0);
+      set_flag(ginf[gArbitrary].flags, qCLOSED, curv > 0);
       set_flag(ginf[gArbitrary].flags, qAFFINE, false);
       geom3::apply_always3();
       }
     else if(ep.eat("e2.")) {
       ginf[gArbitrary].g = giEuclid2;
       ginf[gArbitrary].sides = 7;
-      set_flag(ginf[gArbitrary].flags, qBOUNDED, false);
+      set_flag(ginf[gArbitrary].flags, qCLOSED, false);
       set_flag(ginf[gArbitrary].flags, qAFFINE, false);
       geom3::apply_always3();
       }
     else if(ep.eat("a2.")) {
       ginf[gArbitrary].g = giEuclid2;
       ginf[gArbitrary].sides = 7;
-      set_flag(ginf[gArbitrary].flags, qBOUNDED, false);
+      set_flag(ginf[gArbitrary].flags, qCLOSED, false);
       set_flag(ginf[gArbitrary].flags, qAFFINE, true);
       affine_limit = 200;
       geom3::apply_always3();
@@ -681,14 +681,14 @@ EX void load(const string& fname, bool load_as_slided IS(false), bool keep_slide
     else if(ep.eat("h2.")) {
       ginf[gArbitrary].g = giHyperb2;
       ginf[gArbitrary].sides = 7;
-      set_flag(ginf[gArbitrary].flags, qBOUNDED, false);
+      set_flag(ginf[gArbitrary].flags, qCLOSED, false);
       set_flag(ginf[gArbitrary].flags, qAFFINE, false);
       geom3::apply_always3();
       }
     else if(ep.eat("s2.")) {
       ginf[gArbitrary].g = giSphere2;
       ginf[gArbitrary].sides = 5;
-      set_flag(ginf[gArbitrary].flags, qBOUNDED, true);
+      set_flag(ginf[gArbitrary].flags, qCLOSED, true);
       set_flag(ginf[gArbitrary].flags, qAFFINE, false);
       geom3::apply_always3();
       }
@@ -1504,7 +1504,7 @@ EX void convert() {
   ac.shapes.resize(N);
 
   ginf[gArbitrary].g = cginf.g;
-  ginf[gArbitrary].flags = cgflags & qBOUNDED;
+  ginf[gArbitrary].flags = cgflags & qCLOSED;
   
   for(int i=0; i<N; i++) {
     auto id = identification[old_shvids[i]];
diff --git a/archimedean.cpp b/archimedean.cpp
index ed4472d3..5cc92d43 100644
--- a/archimedean.cpp
+++ b/archimedean.cpp
@@ -419,7 +419,7 @@ geometryinfo1& archimedean_tiling::get_geometry(ld mul) {
 
 void archimedean_tiling::compute_geometry() {
   ginf[gArchimedean].g = get_geometry();
-  set_flag(ginf[gArchimedean].flags, qBOUNDED, get_class() == gcSphere);
+  set_flag(ginf[gArchimedean].flags, qCLOSED, get_class() == gcSphere);
   
   DEBB(DF_GEOM, (format("euclidean_angle_sum = %f\n", float(euclidean_angle_sum))));
   
diff --git a/asonov.cpp b/asonov.cpp
index 0e864e78..35661db2 100644
--- a/asonov.cpp
+++ b/asonov.cpp
@@ -214,7 +214,7 @@ EX int period_xy_edit, period_z_edit;
 EX void set_flags() {
   auto& flag = ginf[gArnoldCat].flags;
   set_flag(flag, qANYQ, period_xy || period_z);
-  set_flag(flag, qBOUNDED, period_xy && period_z);
+  set_flag(flag, qCLOSED, period_xy && period_z);
   set_flag(flag, qSMALL, period_xy && period_z && (period_xy * period_xy * period_z <= 4096));
   set_flag(flag, qHUGE_BOUNDED, period_xy * period_xy * period_z > 16384);
   }
diff --git a/bigstuff.cpp b/bigstuff.cpp
index 4f0db017..1d26a052 100644
--- a/bigstuff.cpp
+++ b/bigstuff.cpp
@@ -2008,7 +2008,7 @@ EX void moreBigStuff(cell *c) {
 EX void generate_mines() {
   vector<cell*> candidates;
 
-  if(bounded)
+  if(closed_or_bounded)
     for(cell *c: currentmap->allcells())
       setdist(c, 7, nullptr);
   
diff --git a/cell.cpp b/cell.cpp
index 536e598b..1d720429 100644
--- a/cell.cpp
+++ b/cell.cpp
@@ -183,7 +183,8 @@ transmatrix hrmap::adj(heptagon *h, int i) { return relative_matrix(h->cmove(i),
 
 vector<cell*>& hrmap::allcells() { 
   static vector<cell*> default_allcells;
-  if(bounded && !(cgflags & qHUGE_BOUNDED) && !(hybri && hybrid::csteps == 0)) {
+  if(disksize) return all_disk_cells;
+  if(closed_manifold && !(cgflags & qHUGE_BOUNDED) && !(hybri && hybrid::csteps == 0)) {
     celllister cl(gamestart(), 1000000, 1000000, NULL);
     default_allcells = cl.lst;
     return default_allcells;
@@ -330,6 +331,24 @@ EX void eumerge(cell* c1, int s1, cell *c2, int s2, bool mirror) {
 
 EX hookset<hrmap*()> hooks_newmap;
 
+EX int req_disksize, disksize;
+EX vector<cell*> all_disk_cells;
+
+EX void init_disk_cells() {
+  disksize = req_disksize;
+  all_disk_cells.clear();
+  if(!disksize) return;
+  celllister cl(currentmap->gamestart(), 1000000, disksize, NULL);
+  all_disk_cells = cl.lst;
+  sort(all_disk_cells.begin(), all_disk_cells.end());
+  }
+
+EX bool is_in_disk(cell *c) {
+  auto it = lower_bound(all_disk_cells.begin(), all_disk_cells.end(), c);
+  if(it == all_disk_cells.end()) return false;
+  return *it == c;
+  }
+
 /** create a map in the current geometry */
 EX void initcells() {
   DEBB(DF_INIT, ("initcells"));
@@ -520,7 +539,7 @@ EX int celldist(cell *c) {
     return hybrid::celldistance(c, currentmap->gamestart());
   if(nil && !quotient) return DISTANCE_UNKNOWN;
   if(euc::in()) return celldistance(currentmap->gamestart(), c);
-  if(sphere || bt::in() || WDIM == 3 || cryst || sn::in() || kite::in() || bounded) return celldistance(currentmap->gamestart(), c);
+  if(sphere || bt::in() || WDIM == 3 || cryst || sn::in() || kite::in() || closed_manifold) return celldistance(currentmap->gamestart(), c);
   #if CAP_IRR
   if(IRREGULAR) return irr::celldist(c, false);
   #endif
@@ -1204,7 +1223,7 @@ EX int celldistance(cell *c1, cell *c2) {
     }
   #endif
   
-  if(bounded) return bounded_celldistance(c1, c2);
+  if(closed_manifold) return bounded_celldistance(c1, c2);
   
   #if CAP_CRYSTAL
   if(cryst) return crystal::precise_distance(c1, c2);
diff --git a/classes.cpp b/classes.cpp
index 3941b1db..0484d4d7 100644
--- a/classes.cpp
+++ b/classes.cpp
@@ -785,7 +785,7 @@ struct geometryinfo {
   eVariation default_variation;
   };
 
-static const flagtype qBOUNDED         = 1;
+static const flagtype qCLOSED         = 1;
 static const flagtype qANYQ            = 2;
 static const flagtype qNONORIENTABLE   = 4;
 static const flagtype qSMALL           = 8;
@@ -835,20 +835,20 @@ extern eVariation variation;
 #endif
 
 #if HDR
-static const flagtype qsNONOR           = qANYQ | qSMALL | qBOUNDED | qNONORIENTABLE;
+static const flagtype qsNONOR           = qANYQ | qSMALL | qCLOSED | qNONORIENTABLE;
 static const flagtype qsNONORE          = qsNONOR | qELLIPTIC;
-static const flagtype qsBQ              = qANYQ | qSMALL | qBOUNDED;
-static const flagtype qsSMALL           = qANYQ | qSMALL | qBOUNDED;
-static const flagtype qsSMALLN          = qANYQ | qSMALL | qBOUNDED | qNONORIENTABLE;
-static const flagtype qsZEBRA           = qANYQ | qSMALL | qBOUNDED | qZEBRA;
-static const flagtype qsFIELD           = qANYQ | qFIELD | qBOUNDED;
-static const flagtype qsDOCKS           = qANYQ | qSMALL | qBOUNDED | qDOCKS;
-static const flagtype qsSMALLB          = qSMALL | qBOUNDED;
+static const flagtype qsBQ              = qANYQ | qSMALL | qCLOSED;
+static const flagtype qsSMALL           = qANYQ | qSMALL | qCLOSED;
+static const flagtype qsSMALLN          = qANYQ | qSMALL | qCLOSED | qNONORIENTABLE;
+static const flagtype qsZEBRA           = qANYQ | qSMALL | qCLOSED | qZEBRA;
+static const flagtype qsFIELD           = qANYQ | qFIELD | qCLOSED;
+static const flagtype qsDOCKS           = qANYQ | qSMALL | qCLOSED | qDOCKS;
+static const flagtype qsSMALLB          = qSMALL | qCLOSED;
 static const flagtype qsSMALLBF         = qsSMALLB | qsFIELD | qANYQ;
 static const flagtype qsSMALLBE         = qsSMALLB | qELLIPTIC | qANYQ;
 static const flagtype qsBP              = qBINARY | qKITE;
 
-static const flagtype qsSINGLE          = qANYQ | qSMALL | qBOUNDED | qSINGLE;
+static const flagtype qsSINGLE          = qANYQ | qSMALL | qCLOSED | qSINGLE;
 #endif
 
 EX geometryinfo1 giEuclid2 = { gcEuclid,     2, 2, 3, {1,1, 0,0 } };
diff --git a/complex.cpp b/complex.cpp
index 44d2a2bd..6758c0fd 100644
--- a/complex.cpp
+++ b/complex.cpp
@@ -15,7 +15,7 @@ EX namespace whirlwind {
   EX int fzebra3(cell *c) {
     if(arcm::in()) return 0;
     if(euclid) {
-      if(bounded) return 0;
+      if(closed_manifold) return 0;
       auto co = euc2_coordinates(c);
       int y = co.second;
       return 1+((((signed short)(y)+int(50000))/3)%3);
@@ -1011,7 +1011,7 @@ EX namespace clearing {
     }
   
   EX void imput(cell *c) {
-    if(bounded) return;
+    if(closed_manifold) return;
     if(score.count(c)) return;
     changes.map_value(score, c);
     auto& is = score[c];
@@ -1216,7 +1216,7 @@ EX namespace mirror {
   #endif
   
   bool noMirrorOn(cell *c) {
-    return c->monst || (!shmup::on && isPlayerOn(c)) || (!bounded && c->cpdist > gamerange());
+    return c->monst || (!shmup::on && isPlayerOn(c)) || (!closed_or_bounded && c->cpdist > gamerange());
     }
 
   bool cellMirrorable(cell *c) {
@@ -3671,6 +3671,53 @@ EX namespace halloween {
   EX cell *dragoncells[4];
   vector<cell*> srch;
 
+  EX void generate() {
+    auto lst = currentmap->allcells();
+    for(cell *c: lst)
+      setdist(c, 7, nullptr);
+
+    halloween::dragoncells[0] = NULL;
+
+    if(sphere && geometry == gNormal) {
+      for(cell *c: lst) {
+        if(GOLDBERG) {
+          int fv = c->master->fiftyval;
+          if(fv == 1 || fv == 4 || fv == 10)
+            c->wall = waChasm;
+          if(c == c->master->c7 && fv == 3)
+            c->item = itTreat;
+          }
+        else if(!BITRUNCATED) {
+          int fv = c->master->fiftyval;
+          if(fv == 1 || fv == 4 || fv == 2)
+            c->wall = waChasm;
+          if(fv == 3) c->item = itTreat;
+          }
+        else {
+          if(c->type == 5) {
+            int fv = c->master->fiftyval;
+            if(fv == 3 || fv == 4 || fv == 2 || fv == 5)
+              c->wall = waChasm;
+            if(fv == 2) halloween::dragoncells[0] = c;
+            if(fv == 5) halloween::dragoncells[3] = c;
+            if(fv == 1) c->item = itTreat;
+            }
+          if(c->type == 6) {
+            int fvset = 0;
+            for(int i=0; i<6; i+=2) fvset |= 1 << createMov(c, i)->master->fiftyval;
+            if(fvset == 35 || fvset == 7) c->wall = waChasm;
+            if(fvset == 7) halloween::dragoncells[1] = c;
+            if(fvset == 35) halloween::dragoncells[2] = c;
+            }
+          }
+        }
+      }
+    else {
+      for(int i=1; i<isize(lst); i+=60) lst[i]->item = itTreat;
+      for(int i=2; i<isize(lst); i+=6) lst[i]->wall = waChasm;
+      }
+    }
+
   cell *farempty(bool lastresort = false) {
     int maxdist = 0;
     vector<cell*> validcells;
diff --git a/complex2.cpp b/complex2.cpp
index ce2637f9..de922d0e 100644
--- a/complex2.cpp
+++ b/complex2.cpp
@@ -531,7 +531,7 @@ EX void count_status() {
   }
 
 EX bool in_minesweeper() {
-  return bounded && specialland == laMinefield;
+  return closed_or_bounded && specialland == laMinefield;
   }
 
 EX bool uncoverMines(cell *c, int lev, int dist, bool just_checking) {
@@ -620,7 +620,7 @@ EX bool safe() {
 
 EX void uncover_full(cell *c2) {
   int mineradius = 
-    bounded ? 3 :
+    closed_or_bounded ? 3 :
     (items[itBombEgg] < 1 && !tactic::on) ? 0 :
     items[itBombEgg] < 20 ? 1 :
     items[itBombEgg] < 30 ? 2 :
diff --git a/config.cpp b/config.cpp
index 3f47ee76..df934093 100644
--- a/config.cpp
+++ b/config.cpp
@@ -934,6 +934,11 @@ EX void initConfig() {
   param_b(vid.smart_area_based, "smart-area-based", false);
   param_i(vid.cells_drawn_limit, "limit on cells drawn", 10000);
   param_i(vid.cells_generated_limit, "limit on cells generated", 250);
+
+  param_i(req_disksize, "disk_size")
+  ->editable(10, 100000, 10, "disk size", "Play on a disk. Enables the special game rules for small bounded spaces (especially relevant for e.g. Minefield and Halloween). The number given is the number of tiles to use; it is not used exactly, actually the smallest disk above this size is used. Set to 0 to disable.", 'd')
+  ->set_sets([] { dialog::bound_low(0); })
+  ->set_reaction([] { if(game_active) { stop_game(); start_game(); } });
   
   #if CAP_SOLV
   addsaver(sn::solrange_xy, "solrange-xy");
diff --git a/crystal.cpp b/crystal.cpp
index 732a506b..7c164751 100644
--- a/crystal.cpp
+++ b/crystal.cpp
@@ -1358,7 +1358,7 @@ EX void set_crystal_period_flags() {
   for(auto& g: ginf)
     if(g.flags & qCRYSTAL) {
       set_flag(ginf[gNil].flags, qSMALL, crystal_period && crystal_period <= 8);
-      set_flag(ginf[gNil].flags, qBOUNDED, crystal_period);
+      set_flag(ginf[gNil].flags, qCLOSED, crystal_period);
       }
   }
 
diff --git a/euclid.cpp b/euclid.cpp
index ec779512..4db630b0 100644
--- a/euclid.cpp
+++ b/euclid.cpp
@@ -149,7 +149,7 @@ EX namespace euc {
 
     vector<cell*> toruscells;  
     vector<cell*>& allcells() override { 
-      if(bounded) {
+      if(closed_manifold && !disksize) {
         if(isize(toruscells) == 0) {
           celllister cl(getOrigin()->c7, 1000, 1000000, NULL);
           toruscells = cl.lst;
@@ -634,7 +634,7 @@ EX namespace euc {
       }
     
     set_flag(ginf[g].flags, qANYQ, eu.infinite_dims < dim);
-    set_flag(ginf[g].flags, qBOUNDED, eu.infinite_dims == 0);
+    set_flag(ginf[g].flags, qCLOSED, eu.infinite_dims == 0);
     set_flag(ginf[g].flags, qSMALL, eu.infinite_dims == 0 && eu.det <= 4096);
     bool nonori = false;
     if(eu.twisted&1) nonori = !nonori;
diff --git a/expansion.cpp b/expansion.cpp
index c16f914b..1df410a6 100644
--- a/expansion.cpp
+++ b/expansion.cpp
@@ -392,7 +392,7 @@ int type_in_quick(expansion_analyzer& ea, cell *c, const cellfunction& f) {
 
 EX bool sizes_known() {
   if(reg3::in_rule()) return true;
-  if(bounded) return false;
+  if(closed_manifold) return false;
   // Castle Anthrax is infinite
   if(bt::in()) return false;
   // not implemented
@@ -717,7 +717,7 @@ string produce_coef_formula(vector<int> coef) {
 
 void expansion_analyzer::view_distances_dialog() {
   static int lastticks;
-  if(scrolling_distances && !bounded) {
+  if(scrolling_distances && !closed_manifold) {
     scrolltime += SDL_GetTicks() - lastticks;
     first_distance += scrolltime / scrollspeed;
     scrolltime %= scrollspeed;
@@ -729,7 +729,7 @@ void expansion_analyzer::view_distances_dialog() {
   dialog::init("");
   cmode |= sm::DIALOG_STRICT_X | sm::EXPANSION;
   
-  int maxlen = bounded ? 128 : 16 + first_distance;
+  int maxlen = closed_manifold ? 128 : 16 + first_distance;
   vector<bignum> qty(maxlen);
   auto& expansion = get_expansion();
   
@@ -748,12 +748,12 @@ void expansion_analyzer::view_distances_dialog() {
     }
   else {
     if(distance_from == dfPlayer) {
-      celllister cl(cwt.at, bounded ? maxlen-1 : gamerange(), 100000, NULL);
+      celllister cl(cwt.at, closed_manifold ? maxlen-1 : gamerange(), 100000, NULL);
       for(int d: cl.dists)
         if(d >= 0 && d < maxlen) qty[d]++;
       }
     else {
-      celllister cl(cwt.at, bounded ? maxlen-1 : gamerange(), 100000, NULL);
+      celllister cl(cwt.at, closed_manifold ? maxlen-1 : gamerange(), 100000, NULL);
       for(cell *c: cl.lst) if((not_only_descendants || is_descendant(c)) && curr_dist(c) < maxlen) qty[curr_dist(c)]++;
       }
     #if !CAP_GMP
diff --git a/fieldpattern.cpp b/fieldpattern.cpp
index 0e304ae2..2902578b 100644
--- a/fieldpattern.cpp
+++ b/fieldpattern.cpp
@@ -1458,7 +1458,7 @@ EX void enableFieldChange() {
   ginf[geometry].distlimit = ginf[gxcur.base].distlimit;
   ginf[geometry].tiling_name = ginf[gxcur.base].tiling_name;
   ginf[geometry].default_variation = ginf[gxcur.base].default_variation;
-  ginf[geometry].flags = qFIELD | qANYQ | qBOUNDED;
+  ginf[geometry].flags = qFIELD | qANYQ | qCLOSED;
   fieldpattern::current_quotient_field.init(gxcur.primes[gxcur.current_prime_id].p);
   }
 
@@ -1473,7 +1473,7 @@ EX void field_from_current() {
   gg.vertex = go.vertex;
   gg.distlimit = go.distlimit;
   gg.tiling_name = go.tiling_name;
-  gg.flags = go.flags | qANYQ | qFIELD | qBOUNDED;
+  gg.flags = go.flags | qANYQ | qFIELD | qCLOSED;
   gg.g = go.g;
   gg.default_variation = go.default_variation;
   fieldpattern::quotient_field_changed = true;  
diff --git a/geom-exp.cpp b/geom-exp.cpp
index 8093adcb..0c6399ee 100644
--- a/geom-exp.cpp
+++ b/geom-exp.cpp
@@ -760,7 +760,7 @@ EX geometry_data compute_geometry_data() {
   if(euclid) gd.euler = 0;
   else if(sphere && nonorientable) gd.euler = 1;
   else if(sphere) gd.euler = 2;
-  else if(!bounded) gd.euler = -2;
+  else if(!closed_manifold) gd.euler = -2;
   else if(WDIM == 3) gd.euler = 0;
   else switch(geometry) {
     case gFieldQuotient:
@@ -810,7 +810,7 @@ EX geometry_data compute_geometry_data() {
     gd.denom /= g;
     }
   
-  if(euclid && bounded) {
+  if(euclid && closed_manifold) {
     gd.worldsize = euc::eu.det;
     if(BITRUNCATED) gd.worldsize *= (a4 ? 2 : 3);
     if(GOLDBERG) gd.worldsize *= cgi.gpdata->area;
@@ -821,7 +821,7 @@ EX geometry_data compute_geometry_data() {
   else 
   gd.worldsize = gd.denom ? gd.nom / gd.denom : 0;
   
-  if(gd.euler < 0 && !bounded)
+  if(gd.euler < 0 && !closed_manifold)
     gd.worldsize = -gd.worldsize;
 
   string spf = its(ts);
@@ -895,6 +895,7 @@ EX geometry_data compute_geometry_data() {
     }
 
   gd.size_str =
+    disksize ? its(isize(currentmap->allcells())) :
     #if CAP_BT
     bt::in() ? fts(8 * M_PI * sqrt(2) * log(2) / pow(vid.binary_width, WDIM-1), 4) + " exp(∞)" :
     #endif
@@ -905,10 +906,10 @@ EX geometry_data compute_geometry_data() {
     #if CAP_CRYSTAL
     cryst ? "∞^" + its(ts/2) :
     #endif
-    WDIM == 3 && bounded ? its(isize(currentmap->allcells())) :
+    WDIM == 3 && closed_manifold ? its(isize(currentmap->allcells())) :
     WDIM == 3 && euclid ? "∞" :
     gd.worldsize < 0 ? (gd.nom%gd.denom ? its(gd.nom)+"/"+its(gd.denom) : its(-gd.worldsize)) + " exp(∞)": 
-    (euclid && quotient && !bounded) ? "∞" :
+    (euclid && quotient && !closed_manifold) ? "∞" :
     gd.worldsize == 0 ? "∞²" :
     its(gd.worldsize);
 
@@ -1057,8 +1058,9 @@ EX void showEuclideanMenu() {
   
   dialog::addBreak(100);
   menuitem_land_structure('l');
+  add_edit(req_disksize);
   
-  if(specialland == laMinefield && bounded) {
+  if(specialland == laMinefield && closed_or_bounded) {
     dialog::addSelItem(XLAT("number of mines"), its(bounded_mine_quantity), 'm');
     dialog::add_action([] {
       dialog::editNumber(bounded_mine_quantity, 0, bounded_mine_max, 1, (bounded_mine_max+5)/10, 
@@ -1129,7 +1131,7 @@ EX void showEuclideanMenu() {
     else if(viewdists) viewdists = false;
     });
 
-  if(bounded) {
+  if(closed_manifold) {
     dialog::addSelItem(XLAT("Euler characteristics"), its(gd.euler), 0);
     if(WDIM == 3) ;
     else if(nonorientable)
diff --git a/geometry2.cpp b/geometry2.cpp
index 0fd07762..4f5cf930 100644
--- a/geometry2.cpp
+++ b/geometry2.cpp
@@ -139,7 +139,7 @@ transmatrix hrmap_standard::relative_matrixh(heptagon *h2, heptagon *h1, const h
     steps++; if(steps > 10000) {
       println(hlog, "not found"); return Id; 
       }
-    if(bounded) {
+    if(closed_manifold) {
       transmatrix T;
       ld bestdist = 1e9;
       for(int d=0; d<S7; d++) {
@@ -817,7 +817,7 @@ EX bool exhaustive_distance_appropriate() {
   if(asonov::in() && asonov::period_xy && asonov::period_xy <= 256) return true;
   #endif
 
-  if(bounded) return true;
+  if(closed_manifold) return true;
 
   return false;
   }
diff --git a/goldberg.cpp b/goldberg.cpp
index d3cc3d6e..a927bafa 100644
--- a/goldberg.cpp
+++ b/goldberg.cpp
@@ -895,7 +895,7 @@ EX namespace gp {
       dialog::addBoolItem(XLAT("irregular"), IRREGULAR, 'i');
       dialog::add_action(dialog::add_confirmation([=] () { 
         if(min_quality && !irr::bitruncations_requested) irr::bitruncations_requested++;
-        if(euclid && (!bounded || nonorientable)) { 
+        if(euclid && (!closed_manifold || nonorientable)) { 
           println(hlog, XLAT("To create Euclidean irregular tesselations, first enable a torus"));
           return;
           }
diff --git a/hyper.h b/hyper.h
index cc45af3d..eb331c57 100644
--- a/hyper.h
+++ b/hyper.h
@@ -152,11 +152,12 @@ void addMessage(string s, char spamtype = 0);
 #define nonorientable (cgflags & qNONORIENTABLE)
 #define elliptic (cgflags & qELLIPTIC)
 #define quotient (cgflags & qANYQ)
-#define smallbounded (cgflags & qSMALL)
-#define bounded (cgflags & qBOUNDED)
+#define smallbounded ((cgflags & qSMALL) || disksize)
+#define closed_manifold (cgflags & qCLOSED)
+#define closed_or_bounded (closed_manifold || disksize)
 
 // Dry Forest burning, heat transfer, etc. are performed on the whole universe
-#define doall (bounded)
+#define doall (closed_or_bounded)
 
 #define sphere_narcm (sphere && !arcm::in())
 
diff --git a/irregular.cpp b/irregular.cpp
index df32e73c..b7b1dc8a 100644
--- a/irregular.cpp
+++ b/irregular.cpp
@@ -1045,7 +1045,7 @@ EX bool ctof(cell* c) {
   }
 
 EX bool supports(eGeometry g) {
-  if(g == gEuclid || g == gEuclidSquare) return ginf[g].flags & qBOUNDED;
+  if(g == gEuclid || g == gEuclidSquare) return ginf[g].flags & qCLOSED;
   return among(g, gNormal, gKleinQuartic, gOctagon, gBolza2, gFieldQuotient, gSphere, gSmallSphere, gTinySphere);
   }
 
diff --git a/items.cpp b/items.cpp
index 054ae1b2..fb2ef883 100644
--- a/items.cpp
+++ b/items.cpp
@@ -79,7 +79,7 @@ EX void pickupMovedItems(cell *c, cell *from) {
   }
 
 EX bool in_lovasz() {
-  return specialland == laMotion && bounded && ls::single() && !daily::on;
+  return specialland == laMotion && closed_or_bounded && ls::single() && !daily::on;
   }
 
 EX int threshold_met(int i) {
diff --git a/landgen.cpp b/landgen.cpp
index d94cb9f4..695d970e 100644
--- a/landgen.cpp
+++ b/landgen.cpp
@@ -184,7 +184,7 @@ EX int hrand_monster(int x) {
   }
 
 EX bool is_zebra_trapdoor(cell *c) {
-  if(euclid && bounded) return false;
+  if(euclid && closed_or_bounded) return false;
   #if CAP_ARCM
   else if(arcm::in() && arcm::current.have_line)
     return arcm::linespattern(c);
@@ -359,7 +359,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
             }
           }
         }
-      else if(PIU(hyperbolic_not37 || (euclid&&bounded) || S7 < 5 || arcm::in() || WDIM == 3)) {
+      else if(PIU(hyperbolic_not37 || (euclid&&closed_or_bounded) || S7 < 5 || arcm::in() || WDIM == 3)) {
         if(fargen) {
           int i = hrand(100);
           if(i < 10) 
@@ -579,7 +579,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
       if(d==8) {
         if(randomPatternsMode)
           c->wall = RANDPAT3(0) ? waCavewall : waCavefloor;
-        else if(euclid && bounded) {
+        else if(euclid && closed_or_bounded) {
           c->wall = waCavefloor;
           }
         else if(nil) {
@@ -685,7 +685,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
         #endif
         else if(arb::in() && arb::current.have_line)
           v = arb::linespattern(c) ? 24 : 16;
-        else if((euclid&&bounded) || hyperbolic_not37 || quotient || arcm::in()) {
+        else if((euclid&&closed_or_bounded) || hyperbolic_not37 || quotient || arcm::in()) {
           v = hrand(100) < 25 ? 24 : 16;
           }
         else if(euclid) {
@@ -760,7 +760,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
       if(d==8) {
         if(randomPatternsMode)
           c->wall = RANDPAT ? waVinePlant : waNone;
-        else if(euclid && bounded) ;
+        else if(euclid && closed_or_bounded) ;
         #if CAP_ARCM
         else if(arcm::in() && arcm::current.have_line)
           c->wall = arcm::linespattern(c) ? waVinePlant : waNone;
@@ -1269,50 +1269,6 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
       break;
     
     case laHalloween:
-      if(fargen) {
-        if(GOLDBERG) {
-          int fv = c->master->fiftyval;
-          if(fv == 1 || fv == 4 || fv == 10) 
-            c->wall = waChasm;
-          if(c == c->master->c7 && fv == 3)
-            c->item = itTreat;
-          }
-        else if(!BITRUNCATED && !euclid) {
-          int fv = c->master->fiftyval;
-          if(fv == 1 || fv == 4 || fv == 2) 
-            c->wall = waChasm;
-          if(fv == 3) c->item = itTreat;
-          }
-        else {
-          if(c->type == 5) {
-            int fv = c->master->fiftyval;
-            if(fv == 3 || fv == 4 || fv == 2 || fv == 5) 
-              c->wall = waChasm;
-            if(fv == 2) halloween::dragoncells[0] = c;
-            if(fv == 5) halloween::dragoncells[3] = c;
-            if(fv == 1) c->item = itTreat;
-            }
-          if(c->type == 6 && !euclid) {
-            int fvset = 0;
-            for(int i=0; i<6; i+=2) fvset |= 1 << createMov(c, i)->master->fiftyval;
-            if(fvset == 35 || fvset == 7) c->wall = waChasm;
-            if(fvset == 7) halloween::dragoncells[1] = c;
-            if(fvset == 35) halloween::dragoncells[2] = c;
-            }
-          }
-        if(quotient && zebra40(c) == 7) {
-          c->item = itTreat;
-          halloween::dragoncells[0] = NULL;
-          }
-        if(quotient && zebra40(c) == 5) {
-          c->wall = waChasm;
-          }
-        if(euclid && bounded) {
-          int i = hrand(100);
-          if(i == 0) c->item = itTreat;
-          else if(i < 5) c->wall = waChasm;
-          }
-        }
       break;
     
     case laWildWest:
@@ -2158,7 +2114,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
       break;
 
     case laMinefield:  
-      if(d == 7 && bounded) c->wall = waMineUnknown;
+      if(d == 7 && closed_or_bounded) c->wall = waMineUnknown;
       else if(d == 7) {
         c->wall = waMineUnknown;
         // 250: rare mines
@@ -2191,7 +2147,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
           c->monst = moBomberbird;
         else placeLocalSpecial(c, 500);
         }
-      if(d == 3 && safety && (c->wall == waMineMine || c->wall == waMineUnknown) && !bounded)
+      if(d == 3 && safety && (c->wall == waMineMine || c->wall == waMineUnknown) && !closed_or_bounded)
         c->wall = waMineOpen;
       break;
     
@@ -2879,7 +2835,7 @@ EX void set_land_for_geometry(cell *c) {
   else if(euc::in(3)) euc::set_land(c);
   #endif
   else if(hybri) setLandHybrid(c);
-  else if(sphere || (euclid && bounded)) setLandSphere(c);
+  else if(sphere || (euclid && closed_or_bounded)) setLandSphere(c);
   else if(euclid) setLandEuclid(c);
   else if(quotient) { setland(c, specialland); setLandQuotient(c); }
   else if(sol) setLandSol(c);
@@ -3058,6 +3014,13 @@ EX void setdist(cell *c, int d, cell *from) {
       }
     }
 
+  if(disksize && !is_in_disk(c)) {
+    setland(c, laMemory);
+    if(!isMultitile(c)) c->monst = moNone;
+    c->item = itNone;
+    c->wall = waChasm;
+    }
+
   ONEMPTY if(!c->item) {
     if(isCrossroads(c->land))
       placeCrossroadOrbs(c);
diff --git a/landlock.cpp b/landlock.cpp
index c0b6fbd0..31131918 100644
--- a/landlock.cpp
+++ b/landlock.cpp
@@ -139,7 +139,7 @@ EX string land_structure_name(bool which) {
   }
 
 EX void fix_land_structure_choice() {  
-  if(bounded) {
+  if(closed_or_bounded) {
     if(land_structure != lsTotalChaos && land_structure != lsChaosRW)
       land_structure = lsSingle;
     }
@@ -155,7 +155,7 @@ EX void fix_land_structure_choice() {
     land_structure = lsSingle;
   if(land_structure == lsPatchedChaos && !(stdeuc || nil || cryst || (euclid && WDIM == 3)))
     land_structure = lsSingle;
-  if(bounded && !among(land_structure, lsChaosRW, lsTotalChaos, lsSingle))
+  if(closed_or_bounded && !among(land_structure, lsChaosRW, lsTotalChaos, lsSingle))
     land_structure = lsSingle;
   }
 
@@ -777,12 +777,12 @@ EX land_validity_t& land_validity(eLand l) {
     return disabled;
   #endif
 
-  if(l == laMinefield && bounded)
+  if(l == laMinefield && closed_or_bounded)
     return special_geo3;
   
   if(l == laAsteroids) {
     if(!shmup::on) return shmup_only;
-    if(!bounded) return bounded_only;
+    if(!closed_manifold) return bounded_only;
     return specially_designed;
     }
   
@@ -901,7 +901,7 @@ EX land_validity_t& land_validity(eLand l) {
     return not_implemented; 
   
   // Halloween needs bounded world (can be big bounded)
-  if(l == laHalloween && !bounded)
+  if(l == laHalloween && !closed_or_bounded)
     return bounded_only;
   
   // Crystal World is designed for nice_dual geometries
@@ -960,7 +960,7 @@ EX land_validity_t& land_validity(eLand l) {
     if(geometry == gBinary4)
       return not_implemented;
     // no equidistants supported in these geometries (big sphere is OK though)
-    if(bounded && !bigsphere)
+    if(closed_or_bounded && !bigsphere)
       return unbounded_only_except_bigsphere;
     // Yendorian only implemented in standard
     if(l == laEndorian && geometry)
@@ -1004,7 +1004,7 @@ EX land_validity_t& land_validity(eLand l) {
   
   if(l == laClearing)
     if(!(stdeucx || geometry == gBinaryTiling || a38 || (a45 && BITRUNCATED) || (a47 && BITRUNCATED)) || NONSTDVAR)
-    if(!bounded)
+    if(!closed_or_bounded)
       return not_implemented;
 
   // does not work in non-bitrunc a4
@@ -1012,7 +1012,7 @@ EX land_validity_t& land_validity(eLand l) {
     return some0;
 
   // does not work in bounded either
-  if(l == laOvergrown && bounded)
+  if(l == laOvergrown && closed_or_bounded)
     return some0;
   
   // horocycle-based lands, not available in bounded geometries nor in Chaos mode
@@ -1023,7 +1023,7 @@ EX land_validity_t& land_validity(eLand l) {
       return not_in_chaos;
       }
     if(arcm::in() || kite::in()) return not_implemented;
-    if(bounded) return unbounded_only;
+    if(closed_or_bounded) return unbounded_only;
     if(INVERSE) return not_implemented;
     }
   
@@ -1064,7 +1064,7 @@ EX land_validity_t& land_validity(eLand l) {
     return technical;
   
   // only in bounded geometry, and not in PTM
-  if(l == laCA && !bounded)
+  if(l == laCA && !closed_or_bounded)
     return bounded_only;
 
   if(l == laCA && tactic::on)
@@ -1121,7 +1121,7 @@ EX land_validity_t& land_validity(eLand l) {
   if(l == laStorms && hyperbolic_not37)
     return pattern_not_implemented_random;
   
-  if(l == laTrollheim && !stdeucx && !bounded)
+  if(l == laTrollheim && !stdeucx && !closed_or_bounded)
     return some1;
 
   if(l == laReptile && sol) return ugly_version_nofull;
@@ -1174,7 +1174,7 @@ EX land_validity_t& land_validity(eLand l) {
   if(l == laPrairie) {
     if(GOLDBERG) return not_implemented;
     else if(stdeucx || (bigsphere && BITRUNCATED && !elliptic) || (geometry == gFieldQuotient)) ;
-    else if(!bounded) return not_implemented;
+    else if(!closed_or_bounded) return not_implemented;
     else return unbounded_only;
     }
   
@@ -1191,10 +1191,10 @@ EX land_validity_t& land_validity(eLand l) {
   if(sol && l == laCamelot)
     return not_implemented;
 
-  if(euclid && quotient && !bounded && l == laCrossroads && euc::sdxy().second == -2 * euc::sdxy().first)
+  if(euclid && quotient && !closed_or_bounded && l == laCrossroads && euc::sdxy().second == -2 * euc::sdxy().first)
     return full_game;
   
-  if(euclid && quotient && !bounded && l == laCrossroads4 && euc::sdxy().second == 0)
+  if(euclid && quotient && !closed_or_bounded && l == laCrossroads4 && euc::sdxy().second == 0)
     return full_game;
   
   // highlight Zebra-based lands on Zebra Quotient!
@@ -1231,7 +1231,7 @@ EX land_validity_t& land_validity(eLand l) {
     return pattern_not_implemented_exclude;
     }
   
-  if(l == laStorms && euclid && bounded) 
+  if(l == laStorms && euclid && closed_manifold)
     return interesting;
   
   if(l == laMagnetic)
diff --git a/mapeditor.cpp b/mapeditor.cpp
index 59e21ea7..d6320d3a 100644
--- a/mapeditor.cpp
+++ b/mapeditor.cpp
@@ -684,7 +684,7 @@ EX namespace mapstream {
   EX hookset<void(fhstream&, int)> hooks_loadmap;
   
   EX cell *save_start() {
-    return (bounded || euclid || prod || arcm::in() || sol || INVERSE) ? currentmap->gamestart() : cwt.at->master->c7;
+    return (closed_manifold || euclid || prod || arcm::in() || sol || INVERSE) ? currentmap->gamestart() : cwt.at->master->c7;
     }
 
 #if CAP_EDIT  
diff --git a/mapeffects.cpp b/mapeffects.cpp
index 176532de..539f2be8 100644
--- a/mapeffects.cpp
+++ b/mapeffects.cpp
@@ -770,9 +770,9 @@ EX bool makeEmpty(cell *c) {
     c->wall = waBoat; // , c->item = itOrbYendor;
   else if(c->land == laMinefield)
     c->wall = waMineOpen;
-  else if(c->wall == waFan && bounded)
+  else if(c->wall == waFan && closed_manifold)
     ;
-  else if(c->wall == waOpenPlate && bounded)
+  else if(c->wall == waOpenPlate && closed_manifold)
     ;
   else if(c->wall == waTrunk || c->wall == waSolidBranch || c->wall == waWeakBranch)
     ;
@@ -786,13 +786,13 @@ EX bool makeEmpty(cell *c) {
     ;
   else if(c->land == laDocks)
     c->wall = waBoat;
-  else if(c->wall == waFreshGrave && bounded)
+  else if(c->wall == waFreshGrave && closed_manifold)
     ;
   else if(c->wall == waBarrier && sphere && WDIM == 3)
     ;
   else if(isReptile(c->wall))
     c->wparam = reptilemax();
-  else if(c->wall == waAncientGrave && bounded)
+  else if(c->wall == waAncientGrave && closed_manifold)
     ;
   else if(c->wall != waRoundTable)
     c->wall = waNone;
diff --git a/menus.cpp b/menus.cpp
index 71343a83..96d922dd 100644
--- a/menus.cpp
+++ b/menus.cpp
@@ -704,7 +704,7 @@ EX void mode_higlights() {
   }  
 
 EX eLandStructure default_land_structure() {
-  if(bounded) return lsSingle;
+  if(closed_or_bounded) return lsSingle;
   if(tactic::on || princess::challenge) return lsSingle;
   if(yendor::on) return yendor::get_land_structure();
   if(specialland == laCanvas) return lsSingle;
@@ -1171,7 +1171,7 @@ EX named_functionality get_o_key() {
 
   dialog::infix = "";
 
-  if((geometry != gNormal || NONSTDVAR) && !daily::on)
+  if((geometry != gNormal || NONSTDVAR || disksize) && !daily::on)
     res.push_back(named_functionality(XLAT("experiment with geometry"), runGeometryExperiments));
   
   if(res.empty()) return named_dialog(XLAT("world overview"), showOverview);
diff --git a/monstergen.cpp b/monstergen.cpp
index a92b8ca9..f69dc222 100644
--- a/monstergen.cpp
+++ b/monstergen.cpp
@@ -335,18 +335,20 @@ EX void wandering() {
   if(cwt.at->land == laCA) ghostcount = 0;
   bool genturn = hrand(100) < 30;
   
-  if(bounded && specialland == laClearing)
+  if(closed_or_bounded && specialland == laClearing)
     clearing::new_root();
 
   if(cwt.at->land == laZebra && cwt.at->wall == waNone && wchance(items[itZebra], 20))
     wanderingZebra(cwt.at);
-  
-  bool smallbounded_generation = smallbounded || (bounded && specialland == laClearing);
-  
+
+  bool smallbounded_generation = smallbounded || (closed_manifold && specialland == laClearing);
+
+  auto valid = [] (cell *c) { if(disksize && !is_in_disk(c)) return false; if(inmirror(c)) return false; return true; };
+
   if(smallbounded_generation) {
     int maxdist = 0;
-    for(int i=0; i<isize(dcal); i++) if(dcal[i]->cpdist > maxdist) maxdist = dcal[i]->cpdist;
-    for(int i=0; i<isize(dcal); i++) if(dcal[i]->cpdist >= maxdist-1) { first7 = i; break; }
+    for(int i=0; i<isize(dcal); i++) if(valid(dcal[i])) if(dcal[i]->cpdist > maxdist) maxdist = dcal[i]->cpdist;
+    for(int i=0; i<isize(dcal); i++) if(valid(dcal[i])) if(dcal[i]->cpdist >= maxdist-1) { first7 = i; break; }
     
     if(hrand(5) == 0) {
       // spawn treasure
@@ -362,10 +364,12 @@ EX void wandering() {
       }
     }
   
+  int iter = 0;
   while(first7 < isize(dcal)) {
+    iter++; if(iter > 1000) break;
     int i = first7 + hrand(isize(dcal) - first7);
     cell *c = dcal[i];
-    if(inmirror(c)) continue;
+    if(!valid(c)) continue;
     if(isPlayerOn(c)) break;
     
     if(specialland == laStorms) {
diff --git a/monstermove.cpp b/monstermove.cpp
index 9ca128b2..7ae8df9a 100644
--- a/monstermove.cpp
+++ b/monstermove.cpp
@@ -1393,7 +1393,7 @@ EX void movehex_rest(bool mounted) {
 EX void movemutant() {
   manual_celllister mcells;
   for(cell *c: currentmap->allcells()) mcells.add(c);
-  if(!bounded) 
+  if(!closed_or_bounded)
     for(int i=0; i<isize(mcells.lst); i++) {
       cell *c = mcells.lst[i];
       if(c->land == laClearing && c->monst != moMutant && !pseudohept(c))
@@ -1427,7 +1427,7 @@ EX void movemutant() {
       if(isPlayerOn(c2)) continue;
 
       if((c2->land == laOvergrown || !pseudohept(c2)) && passable(c2, c, 0)) {
-        if(c2->land == laClearing && !bounded && c2->mpdist > 7) continue;
+        if(c2->land == laClearing && !closed_or_bounded && c2->mpdist > 7) continue;
         c2->monst = moMutant;
         c2->mondir = c->c.spin(j);
         c2->stuntime = mutantphase;
@@ -2096,7 +2096,7 @@ EX void movemonsters() {
   DEBB(DF_TURN, ("leader"));
   if(havewhat & HF_LEADER) groupmove(moPirate, 0);
   DEBB(DF_TURN, ("mutant"));
-  if((havewhat & HF_MUTANT) || (bounded && among(specialland, laOvergrown, laClearing))) movemutant();
+  if((havewhat & HF_MUTANT) || (closed_or_bounded && among(specialland, laOvergrown, laClearing))) movemutant();
   DEBB(DF_TURN, ("bugs"));
   if(havewhat & HF_BUG) hive::movebugs();
   DEBB(DF_TURN, ("whirlpool"));
diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index 27afcf37..0ff8fa0c 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -962,7 +962,7 @@ EX namespace nilv {
     int coords = 0;
     for(int a=0; a<3; a++) if(nilperiod[a]) coords++;
     set_flag(ginf[gNil].flags, qANYQ, coords);
-    set_flag(ginf[gNil].flags, qBOUNDED, coords == 3);
+    set_flag(ginf[gNil].flags, qCLOSED, coords == 3);
     set_flag(ginf[gNil].flags, qSMALL, coords == 3 && nilperiod[0] * nilperiod[1] * nilperiod[2] <= 4096);
     }
 
@@ -1229,7 +1229,7 @@ EX namespace hybrid {
     
     EX void fix_bounded_cycles() {
       if(!rotspace) return;
-      if(!bounded) return;
+      if(!closed_manifold) return;
       in_underlying([&] {
         cellwalker final(currentmap->gamestart(), 0);
         auto& ac = currentmap->allcells();
@@ -1505,7 +1505,7 @@ EX namespace hybrid {
     dialog::extra_options = [=] () { 
       if(rotspace) {
         int e_steps = cgi.psl_steps / gcd(cgi.single_step, cgi.psl_steps); 
-        bool ubounded = PIU(bounded);
+        bool ubounded = PIU(closed_manifold);
         dialog::addSelItem( sphere ? XLAT("elliptic") : XLAT("PSL(2,R)"), its(e_steps), 'P');
         dialog::add_action(set_s(e_steps, true));
         dialog::addSelItem( sphere ? XLAT("sphere") : XLAT("SL(2,R)"), its(2*e_steps), 'P');
diff --git a/pattern2.cpp b/pattern2.cpp
index 9fe0a78f..006bd576 100644
--- a/pattern2.cpp
+++ b/pattern2.cpp
@@ -441,12 +441,12 @@ EX int fieldval_uniq(cell *c) {
     }
   else if(euc::in(2)) {
     auto p = euc2_coordinates(c);
-    if(bounded) return p.first + p.second * (1 << 16);
+    if(closed_manifold) return p.first + p.second * (1 << 16);
     return gmod(p.first - 22 * p.second, 3*127);
     }
   else if(euc::in(3)) {
     auto co = euc::get_ispacemap()[c->master];
-    if(bounded) return co[0] + (co[1] << 10) + (co[2] << 20);
+    if(closed_manifold) return co[0] + (co[1] << 10) + (co[2] << 20);
     return gmod(co[0] + 3 * co[1] + 9 * co[2], 3*127);
     }
   else if(bt::in() || arcm::in() || nil || S3 >= OINF || (cgflags & qIDEAL)) return 0;
@@ -1604,7 +1604,7 @@ EX namespace patterns {
   
   color_t nearer_map(cell *c) {
     if(computed_nearer_map.count(c)) return computed_nearer_map[c];
-    if(!bounded) return 0;
+    if(!closed_manifold) return 0;
 
     cell *sc = currentmap->gamestart();
     auto ac = currentmap->allcells();
@@ -1645,7 +1645,7 @@ EX namespace patterns {
   color_t furthest_map(cell *c, int reduce) {
     auto& cfm = computed_furthest_map;
     if(cfm.count(c)) return cfm[c];
-    if(!bounded) return 0;
+    if(!closed_manifold) return 0;
 
     cell *sc = currentmap->gamestart();
     auto ac = currentmap->allcells();
@@ -2031,7 +2031,7 @@ EX namespace patterns {
       dialog::addSelItem(XLAT("Penrose staircase"), "Nil", '/');
       }
     
-    if(bounded) {
+    if(closed_manifold) {
       dialog::addSelItem(XLAT("nearer end"), "bounded", 'Z');
       dialog::addSelItem(XLAT("furthest from start"), "bounded", 'Y');
       }
diff --git a/quit.cpp b/quit.cpp
index 5b8564f8..d6712d9d 100644
--- a/quit.cpp
+++ b/quit.cpp
@@ -371,7 +371,7 @@ EX void showMission() {
       }
     dialog::addInfo(XLAT("Dropped floors: %1/%2", its(score), its(all)));
     if(score == all) dialog::addInfo(XLAT("CONGRATULATIONS!"), iinf[itOrbYendor].color);
-    if(score == all && geometry == gKleinQuartic && variation == eVariation::untruncated && gp::param == gp::loc(1,1))
+    if(score == all && geometry == gKleinQuartic && variation == eVariation::untruncated && gp::param == gp::loc(1,1) && !disksize)
       achievement_gain_once("LOVASZ", rg::special_geometry);      
     }
   else {  
diff --git a/racing.cpp b/racing.cpp
index 5338b298..5166dbe2 100644
--- a/racing.cpp
+++ b/racing.cpp
@@ -475,7 +475,7 @@ EX void generate_track() {
     }
     
   try {
-  if(bounded && !prod && !(cgflags & qHUGE_BOUNDED)) {
+  if(closed_or_bounded && !prod && !(cgflags & qHUGE_BOUNDED)) {
     bounded_track = true;
     make_bounded_track(s);
     }
@@ -754,7 +754,7 @@ bool inrec = false;
 EX ld race_angle = 90;
 
 EX bool force_standard_centering() {
-  return nonisotropic || hybri || quotient || bounded;
+  return nonisotropic || hybri || quotient || closed_or_bounded;
   }
 
 EX bool use_standard_centering() {
diff --git a/rogueviz/balloonsim.cpp b/rogueviz/balloonsim.cpp
index 5494bd1e..e2848f41 100644
--- a/rogueviz/balloonsim.cpp
+++ b/rogueviz/balloonsim.cpp
@@ -490,7 +490,7 @@ void explore() {
 
   ginf[gArbitrary].g = giEuclid2;
   ginf[gArbitrary].sides = 7;
-  set_flag(ginf[gArbitrary].flags, qBOUNDED, true);
+  set_flag(ginf[gArbitrary].flags, qCLOSED, true);
   set_flag(ginf[gArbitrary].flags, qAFFINE, false);
   geom3::apply_always3();
 
diff --git a/rogueviz/flocking.cpp b/rogueviz/flocking.cpp
index b49bf592..afa0efb5 100644
--- a/rogueviz/flocking.cpp
+++ b/rogueviz/flocking.cpp
@@ -503,8 +503,8 @@ bool drawVertex(const shiftmatrix &V, cell *c, shmup::monster *m) {
   }
   
   void init() {
-    if(!bounded) {
-      addMessage("Flocking simulation needs a bounded space.");
+    if(!closed_manifold) {
+      addMessage("Flocking simulation needs a closed manifold.");
       return;
       }
     stop_game();
diff --git a/rogueviz/janko.cpp b/rogueviz/janko.cpp
index 38364db2..bbde8881 100644
--- a/rogueviz/janko.cpp
+++ b/rogueviz/janko.cpp
@@ -126,7 +126,7 @@ void create_janko() {
   gJanko1 = eGeometry(isize(ginf) - 1);
   // variation = eVariation::pure;
   auto& gi = ginf.back();
-  gi.flags = qANYQ | qBOUNDED | qEXPERIMENTAL;
+  gi.flags = qANYQ | qCLOSED | qEXPERIMENTAL;
   gi.quotient_name = "Janko";
   gi.shortname = "Janko";
   gi.menu_displayed_name = "Janko group J1";
diff --git a/rogueviz/notknot.cpp b/rogueviz/notknot.cpp
index 427149b5..f5f158e9 100644
--- a/rogueviz/notknot.cpp
+++ b/rogueviz/notknot.cpp
@@ -1148,7 +1148,7 @@ void create_notknot() {
     }
   else ginf[gNotKnot] = ginf[base];
   auto& gi = ginf.back();
-  gi.flags |= qANYQ | qBOUNDED | qEXPERIMENTAL | qPORTALSPACE;
+  gi.flags |= qANYQ | qCLOSED | qEXPERIMENTAL | qPORTALSPACE;
   gi.quotient_name = "notknot";
   gi.shortname = "notknot";
   gi.menu_displayed_name = "notknot";
diff --git a/rogueviz/rogueviz.cpp b/rogueviz/rogueviz.cpp
index b37cc7a1..f6f9dccb 100644
--- a/rogueviz/rogueviz.cpp
+++ b/rogueviz/rogueviz.cpp
@@ -602,7 +602,7 @@ bool drawVertex(const shiftmatrix &V, cell *c, shmup::monster *m) {
   
   bool multidraw = quotient;
   
-  bool use_brm = bounded && isize(currentmap->allcells()) <= brm_limit;
+  bool use_brm = closed_or_bounded && isize(currentmap->allcells()) <= brm_limit;
         
   if(!lshiftclick) for(int j=0; j<isize(vd.edges); j++) {
     edgeinfo *ei = vd.edges[j].second;
diff --git a/rogueviz/sag.cpp b/rogueviz/sag.cpp
index fb6e5356..350c5348 100644
--- a/rogueviz/sag.cpp
+++ b/rogueviz/sag.cpp
@@ -63,7 +63,7 @@ namespace sag {
     
   int snakedist(int i, int j) {
     if(i < insnaketab && j < insnaketab) return sdist[i][j];
-    if(bounded) return celldistance(snakecells[i], snakecells[j]);
+    if(closed_manifold) return celldistance(snakecells[i], snakecells[j]);
     int i0 = i, i1 = i, j0 = j, j1 = j;
     int cost = 0;
     // intersect
@@ -77,7 +77,7 @@ namespace sag {
     }
   
   void initSnake(int n) {
-    if(bounded) n = isize(currentmap->allcells());
+    if(closed_or_bounded) n = isize(currentmap->allcells());
     numsnake = n;
     snakecells.resize(numsnake);
     snakefirst.resize(numsnake);
@@ -85,7 +85,7 @@ namespace sag {
     snakenode.resize(numsnake);
     lpbak.resize(numsnake);
     wpbak.resize(numsnake);
-    if(bounded) {
+    if(closed_or_bounded) {
       for(int i=0; i<n; i++) {
         cellwalker cw(currentmap->allcells()[i], 0);
         setsnake(cw, i);
diff --git a/rug.cpp b/rug.cpp
index bfbe4800..af8cc4cc 100644
--- a/rug.cpp
+++ b/rug.cpp
@@ -183,7 +183,7 @@ EX rugpoint *addRugpoint(shiftpoint h, double dist) {
   m->y1 = (1 - onscreen[1] * pconf.scale) / 2;
   m->valid = false;
 
-  if(euclid && quotient && !bounded) {
+  if(euclid && quotient && !closed_manifold) {
     hyperpoint h1 = iso_inverse(models::euclidean_spin) * eumove(euc::eu.user_axes[1]) * C0;
     h1 /= sqhypot_d(2, h1);
     if(nonorientable) h1 /= 2;
@@ -557,7 +557,7 @@ EX void buildRug() {
   need_mouseh = true;
   good_shape = false;
   #if MAXMDIM >= 4
-  if(euclid && bounded) {
+  if(euclid && closed_manifold) {
     good_shape = true;
     buildTorusRug();
     return;
@@ -785,7 +785,7 @@ EX int precision_increases;
 bool stop = false;
 
 EX bool subdivide_further() {
-  if(euclid && bounded) return false;
+  if(euclid && closed_manifold) return false;
   if(GDIM == 3) return false;
   return isize(points) * 4 < vertex_limit;
   }
@@ -794,7 +794,7 @@ EX void subdivide() {
   int N = isize(points);
   // if(euclid && gwhere == gEuclid) return;
   if(!subdivide_further()) {
-    if(euclid && !bounded && gwhere == gEuclid) {
+    if(euclid && !closed_manifold && gwhere == gEuclid) {
       println(hlog, "Euclidean -- full precision");
       stop = true; 
       }
diff --git a/system.cpp b/system.cpp
index a968cca2..c7c34f4e 100644
--- a/system.cpp
+++ b/system.cpp
@@ -346,11 +346,14 @@ EX void initgame() {
     makeEmpty(cwt.at);
     }
   
-  if(specialland == laMinefield && bounded) {
+  if(specialland == laMinefield && closed_or_bounded) {
     bfs();
     generate_mines();
     }
-  
+
+  if(specialland == laHalloween)
+    halloween::generate();
+
   if(in_lovasz()) {
     cwt.at->item = itOrbInvis;
     }
@@ -1455,7 +1458,7 @@ EX void switch_game_mode(char switchWhat) {
       if(tactic::on) firstland = laIce;
       yendor::on = tactic::on = princess::challenge = false;
       land_structure = ls::any_chaos() ? lsNiceWalls : lsChaos;
-      if(bounded) set_geometry(gNormal);
+      if(closed_or_bounded) set_geometry(gNormal);
       racing::on = false;
       break;
 
@@ -1570,6 +1573,7 @@ EX void start_game() {
   #endif
   initcells();
   get_expansion().reset();
+  init_disk_cells();
 
   if(randomPatternsMode) {
     for(int i=0; i<landtypes; i++) {
diff --git a/yendor.cpp b/yendor.cpp
index b74ec97e..23a1e799 100644
--- a/yendor.cpp
+++ b/yendor.cpp
@@ -1234,7 +1234,7 @@ EX namespace peace {
           reset_modes();
           if(peace::on) stop_game_and_switch_mode(rg::peace);
           specialland = firstland = laMinefield;
-          if(!bounded) {
+          if(!closed_or_bounded) {
             geometry = gBring;
             variation = eVariation::goldberg;
             gp::param = gp::loc(2, 1);