fix crown collision check

baumgen.js

@@ -75,6 +75,10 @@ class Crown {
             delete this._path;
         }
     }
+
+    collides(other) {
+        return this._path.intersects(other._path);
+    }
 }
 
 
@@ -172,8 +176,7 @@ class Branch {
 
     }
     collides_crown(other) {
-        return false;
-        //return this._crown.intersects(other._crown);
+        return this.crown.collides(other.crown);
     }
 }