design tool or really cool toy???

I know this is an amazing tool for design - the fact that it takes into consideration the weight of the marbles when they are in the cup just blows my mind! - but just think how much fun this thing would be at home to just play with? Hours and hours of entertainment!! Better than tv! (although I'm still not ready to give up Grey's Anatomy).

Note - in case you are interested this is a new whiteboard design tool created by MIT. You can search it on any web search engine using the phrase MIT sketching.