Played around with a circular map real quick.

maze.cpp

@@ -116,15 +116,13 @@ namespace maze {
     }
   }
 
-  void Builder::hunt_and_kill() {
+  void Builder::hunt_and_kill(Point on) {
     for(auto& room : $rooms) {
       for(matrix::box it{$walls, room.x, room.y, room.width}; it.next();) {
         $walls[it.y][it.x] = 0;
       }
     }
 
-    Point on{1,1};
-
     while(!complete($walls)) {
       auto n = neighbors($walls, on);
       if(n.size() == 0) {