2d

I just stumbled across a very interesting 2D physics simulation program.
I have never seen anything like it before and I think it's really interesting.

From the description at Geekologie.com :

"Phun is a 2D physics environment where you can build/destroy and
otherwise have a jolly good time with all sorts of objects (including
your own). It was programmed by Emil Ernerfeldt (awesome name) of Umeå
University for his CS thesis. It really is awesome and the perfect way
to piss away several days at work."  read more »