Index: exec.c
==================================================================
--- exec.c
+++ exec.c
@@ -1512,11 +1512,11 @@
   if((objects[a]->oflags^objects[b]->oflags)&OF_BIZARRO) return 0;
   return (objects[a]->x==objects[b]->x && objects[a]->y==objects[b]->y);
 }
 
 static Uint32 pat_find_at(int xy,Uint32 m4,Uint32 m5,Uint32 m6,Uint32 m7,Uint8 cl) {
-  Uint8 n=playfield[xy];
+  Uint32 n=playfield[xy];
   Object*o;
   while(n!=VOIDLINK) {
     o=objects[n];
     if(!(o->oflags&(OF_DESTROYED|OF_VISUALONLY))) {
       if(o->misc4.t==TY_SOUND || o->misc4.t==TY_USOUND) Throw("Cannot convert sound to type");
@@ -1565,18 +1565,23 @@
       if(x<1 || x>pfwidth || y<1 || y>pfheight) goto fail;
       break;
     case 0x0200 ... 0x02FF:
       g=code[ptr-1]&255;
       goto message;
-    case 0x1000 ... 0x10FF:
+    case 0x1000 ... 0x11FF:
       g=code[ptr-1]&255;
-      if(g<0x20) n=pat_find_at(x+y*64-65,1UL<<(g&31),0,0,0,0);
-      else if(g<0x40) n=pat_find_at(x+y*64-65,0,1UL<<(g&31),0,0,0);
-      else if(g<0x60) n=pat_find_at(x+y*64-65,0,0,1UL<<(g&31),0,0);
-      else if(g<0x80) n=pat_find_at(x+y*64-65,0,0,0,1UL<<(g&31),0);
-      else n=pat_find_at(x+y*64-65,0,0,0,0,1U<<(g&7));
-      if(n==VOIDLINK) goto fail;
+      if(g<0x20) m=pat_find_at(x+y*64-65,1UL<<(g&31),0,0,0,0);
+      else if(g<0x40) m=pat_find_at(x+y*64-65,0,1UL<<(g&31),0,0,0);
+      else if(g<0x60) m=pat_find_at(x+y*64-65,0,0,1UL<<(g&31),0,0);
+      else if(g<0x80) m=pat_find_at(x+y*64-65,0,0,0,1UL<<(g&31),0);
+      else m=pat_find_at(x+y*64-65,0,0,0,0,1U<<(g&7));
+      if(code[ptr-1]&0x0100) {
+        if(m!=VOIDLINK) goto fail;
+      } else {
+        n=m;
+        if(n==VOIDLINK) goto fail;
+      }
       break;
     case 0x4000 ... 0x7FFF:
       n=obj_class_at(code[ptr-1]&0x3FFF,x,y);
       if(n==VOIDLINK) goto fail;
       break;