i don't think this needs to be just for kids - it's something others could
find useful/fun too. the level set could certainly do with some padding out
with more tutorial levels and then a few more easy levels. i am more than
happy to include new levels in future releases. i am also considering adding
level-pack support so you can download/run a set of levels instead of just
an individual level.

play-wise, i am hesitant to add specific shapes (as this is substantial
work, i'm not convinced about the gain, and once the game starts trying
guess-what-i-mean instead of do-what-i-draw the chances of it getting it
wrong and getting in the way increase).

however there are other ways to make game-play simpler -- that is, make it do
what you mean more often. eg, in v0.2 token friction is reduced so it's
easier to move it when hit from above. there's other parameters that might
be tweaked to change playability:

- reduce friction in general for more motion.

- mass of drawn items (maybe non-linear wrt size?).

- "joint" distance threshold - is it too hard to make joints or do you make
joints where you don't mean to?

- collision logic for joined strokes - currently strokes cannot collide
with strokes they are joined with. this could be extended to cover any
strokes joined to that stroke etc. not sure about this.