diff --git a/.jshintrc b/.jshintrc
index a14fafa..c7d3630 100644
--- a/.jshintrc
+++ b/.jshintrc
@@ -14,6 +14,7 @@
 
     // options
     "laxbreak"      : true,   // Tolerate unsafe line breaks e.g. `return [\n] x` without semicolons.
+    "loopfunc"      : true,   // Allow functions in loops (e.g. for async closures)
 
     // style
     "newcap"        : true,   // Require capitalization of all constructor functions e.g. `new F()`.
diff --git a/demo/dev.html b/demo/dev.html
index 785e7ca..f3b688b 100644
--- a/demo/dev.html
+++ b/demo/dev.html
@@ -18,6 +18,7 @@
         <!-- only required if using MatterTools -->
         <link rel="stylesheet" href="./js/lib/matter-tools/matter-tools.css" type="text/css">
         <script type="text/javascript" src="./js/lib/matter-tools/jquery-1.11.0.min.js"></script>
+        <script type="text/javascript" src="./js/lib/matter-tools/gif/gif.js"></script>
         <script type="text/javascript" src="./js/lib/matter-tools/matter-tools-dev.js"></script>
 
         <!-- matter demo code -->
@@ -34,8 +35,9 @@
                 <select id="demo-select">
                     <option value="mixed">Mixed Shapes</option>
                     <option value="mixedSolid">Solid Rendering</option>
-                    <option value="concave">Concave Bodies</option>
                     <option value="svg">Concave SVG Paths</option>
+                    <option value="terrain">Concave Terrain</option>
+                    <option value="concave">Concave Bodies</option>
                     <option value="compound">Compound Bodies</option>
                     <option value="newtonsCradle">Newton's Cradle</option>
                     <option value="wreckingBall">Wrecking Ball</option>
diff --git a/demo/js/Demo.js b/demo/js/Demo.js
index eed608a..8d0234a 100644
--- a/demo/js/Demo.js
+++ b/demo/js/Demo.js
@@ -1129,7 +1129,11 @@
         
         Demo.reset();
 
-        var particleOptions = { render: { visible: true } };
+        var particleOptions = { 
+            friction: 0.05,
+            frictionStatic: 0.1,
+            render: { visible: true } 
+        };
 
         World.add(_world, [
             Composites.softBody(250, 100, 5, 5, 0, 0, true, 18, particleOptions),
@@ -1422,8 +1426,8 @@
             }
         });
 
-        var vertices = Vertices.fromPath('164 171,232 233,213 302,273 241,342 305,316 231,364 170,309 188,281 117,240 182'),
-            concave = Bodies.fromVertices(200, 200, vertices);
+        var star = Vertices.fromPath('50 0 63 38 100 38 69 59 82 100 50 75 18 100 31 59 0 38 37 38'),
+            concave = Bodies.fromVertices(200, 200, star);
         
         World.add(_world, [stack, concave]);