diff --git a/euclid.cpp b/euclid.cpp
index 5e7b49e6..9e28fbca 100644
--- a/euclid.cpp
+++ b/euclid.cpp
@@ -694,6 +694,7 @@ EX namespace euclid3 {
         cell *c = h->c7;
         if(!do_draw(c, V)) continue;
         drawcell(c, V, 0, false);
+        if(wallopt && isWall3(c) && isize(dq::drawqueue) > 1000) continue;
   
         for(int i=0; i<S7; i++)
           dq::enqueue_by_matrix(h->move(i), V * get_move(h->c7, i));
diff --git a/graph.cpp b/graph.cpp
index 11420843..6e156da7 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -12,6 +12,9 @@ int last_firelimit, firelimit;
 
 EX int inmirrorcount = 0;
 
+/** wall optimization: do not draw things beyond walls */
+EX bool wallopt;
+
 EX bool spatial_graphics;
 EX bool wmspatial, wmescher, wmplain, wmblack, wmascii;
 EX bool mmspatial, mmhigh, mmmon, mmitem;
@@ -4429,6 +4432,8 @@ EX bool isWall3(cell *c, color_t& wcol) {
   return false;
   }
 
+EX bool isWall3(cell *c) { color_t dummy; return isWall3(c, dummy); }
+
 bool isSulphuric(eWall w) { return among(w, waSulphur, waSulphurC); }
 
 // 'land color', but a bit twisted for Alchemist Lab
diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index 52411566..2074da9a 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -387,6 +387,7 @@ EX namespace solnihv {
         cell *c = h->c7;
         if(!do_draw(c, V)) continue;
         drawcell(c, V, 0, false);
+        if(wallopt && isWall3(c) && isize(dq::drawqueue) > 1000) continue;
   
         for(int i=0; i<S7; i++) {
           // note: need do cmove before c.spin
@@ -829,6 +830,7 @@ EX namespace nilv {
         cell *c = h->c7;
         if(!do_draw(c, V)) continue;
         drawcell(c, V, 0, false);
+        if(wallopt && isWall3(c) && isize(dq::drawqueue) > 1000) continue;
 
         if(0) for(int t=0; t<c->type; t++) {
           if(!c->move(t)) continue;
@@ -1507,6 +1509,7 @@ EX namespace rots {
         else {
           drawcell(c, V, 0, false);
           }
+        if(wallopt && isWall3(c) && isize(dq::drawqueue) > 1000) continue;
 
         for(int i=0; i<c->type; i++) {
           cell *c1 = c->cmove(i);
diff --git a/reg3.cpp b/reg3.cpp
index bc0b58b9..aaa6c27b 100644
--- a/reg3.cpp
+++ b/reg3.cpp
@@ -523,6 +523,7 @@ EX namespace reg3 {
         cell *c = h->c7;
         if(!do_draw(c, V)) continue;
         drawcell(c, V, 0, false);
+        if(wallopt && isWall3(c) && isize(dq::drawqueue) > 1000) continue;
     
         for(int d=0; d<S7; d++)
           dq::enqueue_by_matrix(h->move(d), V * tmatrices[h->fieldval][d]);
@@ -812,6 +813,7 @@ EX namespace reg3 {
         cell *c = h->c7;
         if(!do_draw(c, V)) continue;
         drawcell(c, V, 0, false);
+        if(wallopt && isWall3(c) && isize(dq::drawqueue) > 1000) continue;
     
         for(int i=0; i<S7; i++) if(h->move(i)) {
           #if CAP_FIELD
diff --git a/screenshot.cpp b/screenshot.cpp
index 7bd6c4f2..b1a13635 100644
--- a/screenshot.cpp
+++ b/screenshot.cpp
@@ -1064,6 +1064,9 @@ int readArgs() {
     shift_arg_formula(shift_angle);
     shift_arg_formula(movement_angle);
     }
+  else if(argis("-wallopt")) {
+    wallopt = true;
+    }
   else if(argis("-animpar")) {
     ma = maParabolic; 
     shift_arg_formula(parabolic_length);