diff --git a/main_bounce.cpp b/main_bounce.cpp
index 5148df6..6e0c54a 100644
--- a/main_bounce.cpp
+++ b/main_bounce.cpp
@@ -12,7 +12,7 @@
 
 int main(int argc, char** argv) {
 
-    FlatGround* flat = new FlatGround();
+    PerlinGround* flat = new PerlinGround();
     GlutRender& render = GlutRender::get_instance();
     render.init(&argc, argv, 640, 480, "Bouncing stuff");
 
@@ -25,6 +25,7 @@ int main(int argc, char** argv) {
             bbox.low(0), bbox.low(1), bbox.low(2),
             bbox.high(0), bbox.high(1), bbox.high(2));
     render.add_surface(ball.get_surface(), bbox);
+    render.add_surface(flat->get_surface(), bbox_2);
 
 
     GroundFlatMesh ground(Point(0., 0., 0.), 0.05);