http://www.braeunig.us/space/propuls.htm#solid use right arrow, space, and green flag. (green flag resets, arrow changes the shape, and space starts the engine being used up. my simulation is deefinitely not perfect... but it is sort of okay I guess. DOES NOT WORK WELL ONLINE please go see http://scratch.mit.edu/projects/DarthPickley/2935290 (a more recent version of this that uses a smoother approach.)
