diff --git a/js/floor.js b/js/floor.js
index dfff2af..ef4fd76 100644
--- a/js/floor.js
+++ b/js/floor.js
@@ -7,15 +7,20 @@ function createFloor() {
 
   // start with flat floor
   var edges = [
+    new b2.Vec2(-3.5, 4), // back wall
     new b2.Vec2(-3.5, -0.16),
     new b2.Vec2(2.5, -0.16)
   ];
 
   for(var k = 2; k < config.max_floor_tiles; k++) {
-    var ratio = k/config.max_floor_tiles;
-    edges.push(new b2.Vec2(edges[edges.length-1].x + (1  + ratio * Math.random() - ratio/2), edges[edges.length-1].y + (ratio * Math.random() - ratio/2 )));
+    var ratio = k / config.max_floor_tiles;
+    // add uneven floor by continuing from the last point, plus some random jittering
+    edges.push(new b2.Vec2(
+      edges[edges.length - 1].x + (1 + ratio * Math.random() - ratio / 2),
+      edges[edges.length - 1].y + (ratio * Math.random() - ratio / 2)* 2));
 //    edges.push(new b2.Vec2(edges[edges.length-1].x + 1,-0.16));
   }
+  edges.push(new b2.Vec2(edges[edges.length-1].x, edges[edges.length-1].y + 8)); // front wall
   fix_def.shape.CreateChain(edges, edges.length);
   body.CreateFixture(fix_def);
   return body;