old down the left mouse button within the large square and the small square will try to get to your mouse pointer. (You will see a line which represents the force you are applying to the object.) You can move the mouse around while holding the button. Let go to let the box settle. You can also apply random forces to the cube. The structure of this cube isn't too stable, sometimes it can get messed up. Plus, if it moves under the mouse then sometimes IE will highlight the lines! Oh well. It's still kinda cool.