It is fitting that just as the Year of Science 2009 is getting underway, a neat new version of Crayon Physics is available. This is an award-winning 2D physics game for the computer (free as a demo) in which you experience what it would be like if your drawings and doodles acquired the properties of real physical objects with mass and momentum -- balancing, falling, bouncing, and swinging across the screen in a veritable Flatlandian world you create then set in motion. How high can you stack those squares? What's the arc of swing of that hammer? How much weight is needed to counterbalance that lever? Talk about testing an hypothesis against reality.