diff --git a/bigstuff.cpp b/bigstuff.cpp
index 520cac22..9d04fc2e 100644
--- a/bigstuff.cpp
+++ b/bigstuff.cpp
@@ -138,7 +138,9 @@ EX int default_levs() {
     return 1;
   if(S3 >= OINF)
     return 1;
+  #if MAXMDIM >= 4
   if(reg3::in_rule()) return 0;
+  #endif
   return S3-3;
   }
 
@@ -152,7 +154,10 @@ void hrmap::generateAlts(heptagon *h, int levs, bool link_cdata) {
   for(int i=0; i<h->type; i++) 
     createStep(h->alt, i)->alt = h->alt->alt;
   int relspin = -4; // for horocycles it must go the other way
-  if(quotient || reg3::in_rule()) relspin = 0;
+  if(quotient) relspin = 0;
+  #if MAXMDIM >= 4
+  else if(reg3::in_rule()) relspin = 0;
+  #endif
   else {
   for(int j=0; j<h->type; j++) for(int i=0; i<h->type; i++) {
     createStep(h, i);
@@ -194,11 +199,13 @@ void hrmap::generateAlts(heptagon *h, int levs, bool link_cdata) {
     }
   }
 
+#if MAXMDIM >= 4
 EX int hrandom_adjacent(int d) {
   vector<int> choices = {d};
   for(int a=0; a<S7; a++) if(reg3::dirs_adjacent[d][a]) choices.push_back(a);
   return hrand_elt(choices, d);
   }
+#endif
 
 EX heptagon *createAlternateMap(cell *c, int rad, hstate firststate, int special IS(0)) {
 
@@ -211,7 +218,11 @@ EX heptagon *createAlternateMap(cell *c, int rad, hstate firststate, int special
   // check for direction
   int gdir = -1;
   for(int i=0; i<c->type; i++) {
+    #if MAXMDIM >= 4
     if(!reg3::in_rule()) {
+    #else
+    if(true) {
+    #endif
       if(c->move(i) && c->move(i)->mpdist < c->mpdist) gdir = i;
       }
     else {
@@ -283,10 +294,12 @@ EX heptagon *createAlternateMap(cell *c, int rad, hstate firststate, int special
   if(hybri) alt->fieldval = hybrid::get_where(centerover).second;
   alt->c7 = NULL;
   alt->alt = alt;
+  #if MAXMDIM >= 4
   if(reg3::in_rule()) {
     reg3::link_structures(h, alt, firststate);
     if(alt->fiftyval == -1) return nullptr; /* unlinked */
     }
+  #endif
   h->alt = alt;
   alt->cdata = (cdata*) h;
   currentmap->link_alt(bf);
@@ -1499,7 +1512,10 @@ EX void buildBigStuff(cell *c, cell *from) {
     buildBarrier4(c, bd, 0, getNewLand(c->land), c->land); */
     }
       
-  if((!chaosmode) && bearsCamelot(c->land) && is_master(c) && !bt::in() && !(hyperbolic && WDIM == 3 && !reg3::in_rule()) && 
+  if((!chaosmode) && bearsCamelot(c->land) && is_master(c) && !bt::in() && 
+    #if MAXMDIM >= 4
+    !(hyperbolic && WDIM == 3 && !reg3::in_rule()) && 
+    #endif
     (quickfind(laCamelot) || peace::on || (hrand(I2000) < (c->land == laCrossroads4 ? 800 : 200) && horo_ok() && 
     items[itEmerald] >= U5 && !tactic::on && !racing::on))) {
     int rtr = newRoundTableRadius();
diff --git a/cell.cpp b/cell.cpp
index c805d3bb..283756b6 100644
--- a/cell.cpp
+++ b/cell.cpp
@@ -148,8 +148,10 @@ EX hrmap *currentmap;
 EX vector<hrmap*> allmaps;
 
 EX hrmap *newAltMap(heptagon *o) { 
+  #if MAXMDIM >= 4
   if(reg3::in_rule())
     return reg3::new_alt_map(o);
+  #endif
   return new hrmap_hyperbolic(o); 
   }
 // --- hyperbolic geometry ---
@@ -524,11 +526,13 @@ EX int celldistAlt(cell *c) {
 /** direction upwards in the tree */
 EX int updir(heptagon *h) {
   if(bt::in()) return bt::updir();
+  #if MAXMDIM >= 4
   if(WDIM == 3 && reg3::in_rule()) {
     for(int i=0; i<S7; i++) if(h->move(i) && h->move(i)->distance < h->distance) 
       return i;
     return -1;
     }
+  #endif
   if(h->distance == 0) return -1;
   return 0;
   }
@@ -536,11 +540,13 @@ EX int updir(heptagon *h) {
 /** direction upwards in the alt-tree */
 EX int updir_alt(heptagon *h) {
   if(euclid || !h->alt) return -1;
+  #if MAXMDIM >= 4
   if(WDIM == 3 && reg3::in_rule()) {
     for(int i=0; i<S7; i++) if(h->move(i) && h->move(i)->alt && h->move(i)->alt->distance < h->alt->distance) 
       return i;
     return -1;
     }
+  #endif
   for(int i=0; i<S7; i++)
     if(h->move(i) && h->move(i)->alt == h->alt->move(0)) 
       return i;
diff --git a/celldrawer.cpp b/celldrawer.cpp
index b20bf06e..1aa1cd73 100644
--- a/celldrawer.cpp
+++ b/celldrawer.cpp
@@ -872,10 +872,12 @@ void celldrawer::draw_halfvine() {
     queuepolyat(GDIM == 2 ? Vdepth : V2, cgi.shSemiFloor[0], darkena(vcol, fd, 0xFF), PPR::WALL3A);
     {dynamicval<color_t> p(poly_outline, OUTLINE_TRANS); queuepolyat(V2 * spin(M_PI*2/3), cgi.shSemiFloorShadow, SHADOW_WALL, GDIM == 2 ? PPR::WALLSHADOW : PPR::TRANSPARENT_SHADOW); }
     auto& side = queuepolyat(V2, cgi.shSemiFloorSide[SIDE_WALL], darkena(vcol, fd, 0xFF), PPR::WALL3A-2+away(V2));
+    #if MAXMDIM >= 4
     if(GDIM == 3 && qfi.fshape) {
       side.tinf = &floor_texture_vertices[shar.id];
       ensure_vertex_number(*side.tinf, side.cnt);
       }
+    #endif
 
     if(cgi.validsidepar[SIDE_WALL]) forCellIdEx(c2, j, c) {
       int dis = i-j;
@@ -1529,6 +1531,7 @@ void celldrawer::draw_features() {
   }
 
 void celldrawer::draw_features_and_walls_3d() {
+#if MAXMDIM >= 4
   color_t dummy;
   int ofs = wall_offset(c);
   if(isWall3(c, wcol)) {
@@ -1645,6 +1648,7 @@ void celldrawer::draw_features_and_walls_3d() {
     queuepoly(face_the_player(V), cgi.shLoveRing, darkena(0x804060, 0, 0xFF));
   if(rd == 2) 
     queuepoly(face_the_player(V), cgi.shLoveRing, darkena(0x402030, 0, 0xFF));
+#endif
   }
 
 #if HDR
diff --git a/fieldpattern.cpp b/fieldpattern.cpp
index edca935f..ffe70c18 100644
--- a/fieldpattern.cpp
+++ b/fieldpattern.cpp
@@ -299,6 +299,9 @@ struct fpattern {
   
   unsigned compute_hash();
 
+  void set_field(int p, int sq);
+
+  #if MAXMDIM >= 4
   // general 4D
   vector<transmatrix> fullv;
 
@@ -308,12 +311,10 @@ struct fpattern {
   int solve3();
   bool generate_all3();
 
-  void set_field(int p, int sq);
-  // transmatrix full_R, full_P, full_X;
-  
   #if CAP_THREAD
   struct discovery *dis;
   #endif
+  #endif
   };
 
 #if CAP_THREAD
@@ -377,6 +378,7 @@ vector<matrix> fpattern::generate_isometries() {
   return res;
   }
 
+#if MAXMDIM >= 4
 vector<matrix> fpattern::generate_isometries3() {
   
   matrix T = Id;
@@ -454,6 +456,7 @@ void fpattern::add1(const matrix& M, const transmatrix& Full) {
     matcode[M] = i, matrices.push_back(M), fullv.push_back(Full);
     }
   }
+#endif
 
 map<unsigned,int> hash_found;
 
@@ -469,6 +472,7 @@ unsigned fpattern::compute_hash() {
   return hashv;
   }
 
+#if MAXMDIM >= 4
 bool fpattern::generate_all3() {
 
   reg3::generate_fulls();
@@ -554,6 +558,7 @@ int fpattern::solve3() {
   
   return cmb;
   }
+#endif
 
 void fpattern::set_field(int p, int sq) {
   Prime = p;
@@ -586,6 +591,7 @@ int fpattern::solve() {
         }
       } else wsquare = 0;
 
+    #if MAXMDIM >= 4
     if(WDIM == 3) {
       if(dual == 0 && (Prime <= limitsq || pw == 1)) {
         int s = solve3();
@@ -593,6 +599,7 @@ int fpattern::solve() {
         }
       continue;
       }
+    #endif
 
     if(dual == 2) {
       if(Field <= 10) {
@@ -1325,7 +1332,9 @@ EX void hread_fpattern(hstream& hs, fieldpattern::fpattern& fp) {
   hread(hs, fp.R);
   hread(hs, fp.X);
   fp.set_field(fp.Prime, fp.wsquare);
+  #if MAXMDIM >= 4
   fp.generate_all3();
+  #endif
   }
 
 EX void hwrite_fpattern(hstream& hs, fieldpattern::fpattern& fp) {
diff --git a/graph.cpp b/graph.cpp
index f07eef40..c9a11061 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -3603,12 +3603,14 @@ EX bool fat_edges = false;
 EX void gridline(const transmatrix& V1, const hyperpoint h1, const transmatrix& V2, const hyperpoint h2, color_t col, int prec) {
   ld d = hdist(V1*h1, V2*h2);
   
+  #if MAXMDIM >= 4
   if(WDIM == 3 && fat_edges) {
     transmatrix T = V1 * rgpushxto0(h1);
     transmatrix S = rspintox(inverse(T) * V2 * h2);
     queuepoly(T * S, cgi.generate_pipe(d, vid.linewidth), col);
     return;
     }
+  #endif
 
   while(d > precise_width && d < 100 && grid_depth < 10) { 
     if(!eqmatrix(V1, V2, 1e-6)) { gridline(V1, h1, V1, inverse(V1) * V2 * h2, col, prec); return; }
diff --git a/landgen.cpp b/landgen.cpp
index 25b42243..20c2bbcc 100644
--- a/landgen.cpp
+++ b/landgen.cpp
@@ -667,6 +667,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
         #endif
         else if(arb::in() && arb::current.have_line)
           c->wall = arb::linespattern(c) ? waTrapdoor : waNone;
+        #if MAXMDIM >= 4
         else if(reg3::in_rule()) switch(geometry) {
           case gSpace534: {
             if(c->master->fieldval == 0) c->wall = waTrapdoor;
@@ -690,6 +691,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
             }
           default: ;
           }
+        #endif
         else if(euclid && !arcm::in()) {
           auto co = euc2_coordinates(c);
           int y = co.second;