diff --git a/attack.cpp b/attack.cpp
index 6c9447a5..f3971189 100644
--- a/attack.cpp
+++ b/attack.cpp
@@ -758,7 +758,7 @@ EX void killMonster(cell *c, eMonster who, flagtype deathflags IS(0)) {
   if(m == moWaterElemental && c->item == itNone)
     c->item = itOrbWater;
 
-  if(m == moPirate && isOnCIsland(c) && c->item == itNone && (
+  if(m == moPirate && (isOnCIsland(c) || ls::hv_structure()) && c->item == itNone && (
       eubinary ||
       (c->master->alt && celldistAlt(c) <= 2-getDistLimit()) ||
       isHaunted(c->land)) && !cryst) {
diff --git a/bigstuff.cpp b/bigstuff.cpp
index 7e53b983..bdd5ee29 100644
--- a/bigstuff.cpp
+++ b/bigstuff.cpp
@@ -1657,9 +1657,12 @@ EX void start_camelot(cell *c) {
   if(alt) {
     altmap::radius(alt) = rtr;
     altmap::orig_land(alt) = c->land;
+    horodisk_land[alt] = laCamelot;
     }
   }
 
+EX map<heptagon*, eLand> horodisk_land;
+
 EX void build_horocycles(cell *c, cell *from) {
 
   bool deepOcean = deep_ocean_at(c, from);
@@ -1708,10 +1711,18 @@ EX void build_horocycles(cell *c, cell *from) {
   if(c->land == laCaribbean && can_start_horo(c))
     create_altmap(c, horo_gen_distance(), hsA);
 
+  if(ls::horodisk_structure() && can_start_horo(c)) {
+    auto m = create_altmap(c, horo_gen_distance(), hsA);
+    if(m) {
+      horodisk_land[m] = getNewLand(laCrossroads);
+      clearing::bpdata[m].root = NULL;
+      }
+    }
+
   if(c->land == laCanvas && can_start_horo(c) && ls::any_order())
     create_altmap(c, horo_gen_distance(), hsA);
 
-  if(c->land == laPalace && can_start_horo(c) && !princess::generating && !shmup::on && multi::players == 1 && !weirdhyperbolic &&
+  if(c->land == laPalace && can_start_horo(c) && !princess::generating && !shmup::on && multi::players == 1 && !weirdhyperbolic && !ls::hv_structure() &&
     (princess::forceMouse ? canReachPlayer(from, moMouse) :
       (hrand(2000) < (peace::on ? 100 : 20))) && 
     (princess::challenge || kills[moVizier] || peace::on)) {
@@ -1966,12 +1977,31 @@ EX void moreBigStuff(cell *c) {
     else
       c->wall = waSea;
     }
+
+  if(ls::horodisk_structure()) {
+    if(have_alt(c) && masterAlt(c) <= 0) {
+      gen_alt(c);
+      preventbarriers(c);
+      }
+    if(have_alt(c) && celldistAlt(c) <= 0) {
+      eLand l = horodisk_land[c->master->alt->alt];
+      setland(c, l);
+      if(l == laWhirlpool && celldistAlt(c) >= -1) {
+        setland(c, laOcean);
+        c->landparam = 30;
+        }
+      if(l == laCaribbean) generateTreasureIsland(c);
+      if(isEquidLand(l)) c->landparam = 1-celldistAlt(c);
+      }
+    else
+      setland(c, laCrossroads);
+    }
   
   extend_alt(c, laPalace, laPalace, false, PRADIUS1);
 
   extend_alt(c, laCanvas, laCanvas);
 
-  if(extend_alt(c, laStorms, laStorms, false)) {
+  if(extend_alt(c, laStorms, laStorms, false) && !ls::hv_structure()) {
     int d = celldistAlt(c);
     if(d <= -2) {
       c->wall = eubinary ? waCharged : (altmap::which(c->master->alt->alt) & 1) ? waCharged : waGrounded;
@@ -1990,10 +2020,12 @@ EX void moreBigStuff(cell *c) {
         c->wall = waColumn;
     }
   
-  else if(extend_alt(c, laTemple, laRlyeh)) 
+  else if(extend_alt(c, laTemple, laRlyeh) && !ls::hv_structure())
     gen_temple(c);
 
-  if(extend_alt(c, laClearing, laOvergrown)) {
+   if(c->land == laTemple && ls::hv_structure()) gen_temple(c);
+
+  if(extend_alt(c, laClearing, laOvergrown) && !ls::hv_structure()) {
     if(in_single_horo(c, laClearing)) {
       c->land = laClearing, c->wall = waNone;
       }
@@ -2001,11 +2033,16 @@ EX void moreBigStuff(cell *c) {
       c->wall = waSmallTree, c->monst = moNone, c->item = itNone, c->landparam = 1;
     }
 
-  if(extend_alt(c, laMountain, laJungle) && in_single_horo(c, laMountain)) {
+  if(c->land == laClearing && ls::hv_structure()) {
+    if(celldistAlt(c) >= -1)
+      c->wall = waSmallTree, c->monst = moNone, c->item = itNone, c->landparam = 1;
+   }
+
+  if(extend_alt(c, laMountain, laJungle) && in_single_horo(c, laMountain) && !ls::hv_structure()) {
     c->land = laMountain, c->wall = waNone;
     }
 
-  if(extend_alt(c, laWhirlpool, laOcean) && in_single_horo(c, laWhirlpool))
+  if(!ls::horodisk_structure() && extend_alt(c, laWhirlpool, laOcean) && in_single_horo(c, laWhirlpool))
     c->land = laWhirlpool, c->wall = waSea, c->monst = moNone, c->item = itNone;
   }
 
diff --git a/complex.cpp b/complex.cpp
index 2de76a18..bc8049b1 100644
--- a/complex.cpp
+++ b/complex.cpp
@@ -907,6 +907,8 @@ EX namespace clearing {
         c->mondir = 0;
       return;
       }
+
+    if(c->land == laClearing && ls::hv_structure() && celldistAlt(c) >= -1) return;
     
     if(!eubinary && !horo_ok()) return;
     // cell *oc = c;
@@ -4080,10 +4082,18 @@ EX namespace dungeon {
           rdepths[i] = c2 && c3 && c4 && (c2->landflags == 3 || c3->landflags == 3 || c4->landflags == 3);
           if(c2) generate_around(c2);
           if(c3) generate_around(c3);
-          c2 = ts::left_parent(c2, coastvalEdge);
-          c3 = ts::right_parent(c3, coastvalEdge);
-          if(!c2) { towerError(c); return; }
-          if(!c3) { towerError(c); return; }
+          
+          if(ls::horodisk_structure()) {
+            c2 = ts::left_child(c2, celldistAlt);
+            c3 = ts::right_child(c3, celldistAlt);
+            if(!c2 || !c3) return;
+            }
+          else {
+            c2 = ts::left_parent(c2, coastvalEdge);
+            c3 = ts::right_parent(c3, coastvalEdge);
+            if(!c2) { towerError(c); return; }
+            if(!c3) { towerError(c); return; }
+            }
           }
         }
       
@@ -4106,10 +4116,17 @@ EX namespace dungeon {
           if(c3 && c5 && c5->landflags == 3 && c3->landflags != 3 && c5 == ts::right_of(c3, coastvalEdge))
             c->wall = waLadder;
           buildEquidistant(c4); buildEquidistant(c5);
-          if(c2) c2 = ts::left_parent(c2, coastvalEdge);
-          if(c3) c3 = ts::right_parent(c3, coastvalEdge);
-          if(c4) c4 = ts::left_parent(c4, coastvalEdge);
-          if(c5) c5 = ts::right_parent(c5, coastvalEdge);
+          if(ls::horodisk_structure()) {
+            c2 = ts::left_child(c2, celldistAlt);
+            c3 = ts::right_child(c3, celldistAlt);
+            if(!c2 || !c3) return;
+            }
+          else {
+            if(c2) c2 = ts::left_parent(c2, coastvalEdge);
+            if(c3) c3 = ts::right_parent(c3, coastvalEdge);
+            if(c4) c4 = ts::left_parent(c4, coastvalEdge);
+            if(c5) c5 = ts::right_parent(c5, coastvalEdge);
+            }
           }
         }
       }
@@ -4161,10 +4178,17 @@ EX namespace dungeon {
             switchcount++;
           generate_around(c2);
           generate_around(c3);
-          c2 = ts::left_parent(c2, coastvalEdge);
-          c3 = ts::right_parent(c3, coastvalEdge);
-          if(!c2) { towerError(c); return 0; }
-          if(!c3) { towerError(c); return 0; }
+          if(ls::horodisk_structure()) {
+            c2 = ts::left_child(c2, celldistAlt);
+            c3 = ts::right_child(c3, celldistAlt);
+            if(!c2 || !c3) return 0;
+            }
+          else {
+            c2 = ts::left_parent(c2, coastvalEdge);
+            c3 = ts::right_parent(c3, coastvalEdge);
+            if(!c2) { towerError(c); return 0; }
+            if(!c3) { towerError(c); return 0; }
+            }
           }
         }
       }
diff --git a/landgen.cpp b/landgen.cpp
index ef01f1f5..9437c9af 100644
--- a/landgen.cpp
+++ b/landgen.cpp
@@ -276,7 +276,7 @@ EX void place_random_gate_continuous(cell *c) {
   }
 
 EX void giantLandSwitch(cell *c, int d, cell *from) {
-  bool fargen = d == min(BARLEV, 9);
+  bool fargen = d == min(BARLEV, ls::horodisk_structure() ? 8 : 9);
   switch(c->land) {
 
     case laPrairie: // -------------------------------------------------------------
@@ -405,7 +405,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
         }
       else {
 
-        if(d == 9) {
+        if(d == (ls::horodisk_structure() ? 8 : 9)) {
           cell *c2 = NONSTDVAR ? c->master->c7 : c;
           if(cdist50(c2) == 3 && polarb50(c2))
             c->wall = waPalace;
@@ -453,7 +453,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
             }          
         
           // note: Princess Challenge brings back the normal Palace generation
-          bool lookingForPrincess = !euclid && c->master->alt && !princess::challenge;
+          bool lookingForPrincess = !euclid && c->master->alt && !princess::challenge && !ls::horodisk_structure();
           
           bool pgate = false;
           if(PURE || GOLDBERG) {
@@ -551,7 +551,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
         }
       
       ONEMPTY {
-        bool lookingForPrincess0 = !euclid && c->master->alt;
+        bool lookingForPrincess0 = !euclid && c->master->alt && !ls::horodisk_structure();
         bool lookingForPrincess = lookingForPrincess0 && !princess::challenge;
         int hardness = lookingForPrincess ? 5 : items[itPalace] + yendor::hardness();
         
@@ -1982,7 +1982,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
         for(int i=0; i<c->type; i++) {
           cell *c2 = c->move(i);          
           if(c2 && c2->wall == waRose) nww++;
-          if(c2 && !ls::any_chaos()) for(int j=0; j<c2->type; j++) {
+          if(c2 && !ls::any_chaos() && !ls::hv_structure()) for(int j=0; j<c2->type; j++) {
             cell *c3 = c2->move(j);
             // note: c3->land is required for Android --
             // not strictly equivalent since another land there might be not yet generated
@@ -2089,6 +2089,12 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
     case laOcean:
       if(d >= 8) c->wall = waSea;
       if(d == 7 && !safety) {
+
+        if(ls::horodisk_structure() && c->master->alt && horodisk_land[c->master->alt->alt] == laWhirlpool) {
+          if(hrand(100) < 10) c->wall = waBoat;
+          return;
+          }
+
         bool placecolumn = false;
         if(c->landparam % temple_layer_size() == 0 && c->landparam <= 24) {
           int q = 0;
@@ -2261,6 +2267,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
     case laClearing:    
       if(d == 7) {
         clearing::generate(c);
+        if(ls::horodisk_structure() && celldistAlt(c) >= -1) c->monst = moNone;
         if(pseudohept(c)) {
           int d = -celldistAlt(c);
           if(hrand_monster(2500) < items[itMutant2] + yendor::hardness() - 10 && !reptilecheat)
@@ -2460,6 +2467,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
           int freq = 4000;
           if(ls::single() && specialland == laCrossroads5 && !racing::on)
             freq = 250;
+          if(ls::hv_structure() && hrand(10000) < 10) { c->monst = moPirate; }
           if(hrand_monster(freq) < items[itHyperstone] && !c->monst) {
             // only interesting monsters here!
             eMonster cm = crossroadsMonster();
@@ -2533,7 +2541,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
             
     case laEclectic: {
 
-      if(d >= 9) c->wall = waChasm;
+      if(d >= (ls::hv_structure() ? 8 : 9)) c->wall = waChasm;
       
       if(d == 8) wfc::schedule(c);
 
diff --git a/landlock.cpp b/landlock.cpp
index f219bacd..fb903721 100644
--- a/landlock.cpp
+++ b/landlock.cpp
@@ -532,7 +532,7 @@ EX eLand getNewLand(eLand old) {
   // the intermediate lands
   if(all_unlocked || gold() >= R30) {
     tab[cnt++] = laCrossroads;
-    tab[cnt++] = geometry ? laMirrorOld : laMirror;
+    tab[cnt++] = (geometry || ls::hv_structure()) ? laMirrorOld : laMirror;
     tab[cnt++] = laOcean;
     tab[cnt++] = laLivefjord;
     if(all_unlocked || kills[moVizier]) tab[cnt++] = laEmerald;
@@ -548,7 +548,7 @@ EX eLand getNewLand(eLand old) {
     if(all_unlocked || rlyehComplete()) tab[cnt++] = laRlyeh;
     else if(ls::std_chaos() && (old == laWarpCoast || old == laLivefjord || old == laOcean)) 
       tab[cnt++] = laRlyeh;
-    if((all_unlocked || items[itStatue] >= U5) && ls::std_chaos())
+    if((all_unlocked || items[itStatue] >= U5) && (ls::std_chaos() || ls::horodisk_structure()))
       tab[cnt++] = laTemple;
     if(old == laCrossroads || old == laCrossroads2) tab[cnt++] = laOcean;
     if(old == laOcean) tab[cnt++] = laCrossroads;
@@ -563,6 +563,9 @@ EX eLand getNewLand(eLand old) {
     tab[cnt++] = laDual;
     tab[cnt++] = laSnakeNest;
     }
+
+  if(landUnlocked(laMountain)) tab[cnt++] = laMountain;
+  if(landUnlocked(laClearing)) tab[cnt++] = laClearing;
   
   if(landUnlocked(laTrollheim)) {
     if(isTrollLand(old)) LIKELY tab[cnt++] = laTrollheim;
@@ -731,6 +734,7 @@ namespace lv {
   land_validity_t not_in_shmup = {0, q0, "This land is not available in the shmup mode."}; 
   land_validity_t not_in_multi = {0, q0, "This land is not available in multiplayer."}; 
   land_validity_t single_only = {2, q0 | switch_to_single, "Available in single land mode only." };
+  land_validity_t not_in_hv = { 0, q0, "Does not work in horodisk/Voronoi mode."};
   }
 
 // old Daily Challenges should keep their validity forever
@@ -853,6 +857,8 @@ EX land_validity_t& land_validity(eLand l) {
     if(l == laBurial && !shmup::on) return not_implemented;
     if(l == laMirrorOld && !shmup::on) return not_implemented;
     }
+
+  if(ls::hv_structure() && among(l, laPrairie, laIvoryTower, laDungeon, laEndorian, laBrownian, laTortoise, laElementalWall)) return not_in_hv;
   
   if(l == laBrownian) {
     if(quotient || !hyperbolic || cryst) return dont_work;
@@ -935,12 +941,14 @@ EX land_validity_t& land_validity(eLand l) {
   if(l == laWhirlwind && hyperbolic_not37)
     return pattern_incompatibility;
 
+  bool better_mirror = !geometry && STDVAR && !ls::hv_structure();
+
   // available only in non-standard geometries
-  if(l == laMirrorOld && !geometry && STDVAR)
+  if(l == laMirrorOld && better_mirror)
     return better_version_exists;
   
   // available only in standard geometry
-  if(l == laMirror && (geometry || NONSTDVAR))
+  if(l == laMirror && !better_mirror)
     return not_implemented; 
   
   // Halloween needs bounded world (can be big bounded)
diff --git a/system.cpp b/system.cpp
index 7c7b9737..9038d1c1 100644
--- a/system.cpp
+++ b/system.cpp
@@ -1770,6 +1770,7 @@ auto cgm = addHook(hooks_clearmemory, 40, [] () {
   crush_next.clear(); 
   crush_now.clear();
   rosemap.clear();
+  horodisk_land.clear();
   for(auto &am: adj_memo) am.clear();
   }) + 
 addHook(hooks_gamedata, 0, [] (gamedata* gd) {