objects.add(icosahedron);
                var helper = new THREE.BoxHelper(icosahedron, 0xff0000);
                icosahedron.limit = WALL_LIMIT - helper.geometry.boundingSphere.radius;
            }

            /**
             *  Create a set of vertices that represent the AABB box from BoxHelper
             *
             *     5____4
             *   1/___0/|
             *   | 6__|_7
             *   2/___3/
             *
             *  0: max.x, max.y, max.z
             *  1: min.x