Apparently, the version I downloaded kept getting corrupted. Since I don't know how to clear a cache (other than with a shovel and a broom, that is) I downloaded it from my pc and copied the deb to my card.

I'm happy to say the install went well and -- sofar -- Numptyphysics runs almost perfectly. One exception: the "hold ESC to quit" doesn't seem to work, but killing from the home screen does a fine job.

It's a very very nice program, but I'm still pining for a variation I outlined on the CrayonPhysics site: Instead of a puzzle-solver, I'd like to see it as a freeform drawing program for kids. It's a nice way for younger children to create animations and a sort of virtual Legos.

Perhaps a series of predefined shapes could be added as a side-toolbar: wheels, levers, standard building blocks, even legs and arms that perform pre-defined motions. Ow, I dunno, I'm just making this up as I go along.