It could use a "start again" option so one wouldn't have to reload the page. Also a "pause and draw" would be helpful.
And some colours...
I do like that each "stroke" basically turns into one plane and when you wait a moment and add some more stars it's like another plane at an angle. And if you do it right, you can get an effect that - although the simulation turns linearly all the time - some parts appear to stop while others continue their rotation (and sometimes even seemingly speed up).