Algodoo

A bit more expansive than my last upload of hacked airfriction parts, this one has circles too. Red is 1000X normal air friction, blue is -1000X (accelerates wildly in air), and this one also has a gray circle and block that experience zero air friction. Used some of these to make my "faster car in Phun".

This WILL NOT mess with your config. Clone, rescale, save as a phunlet and use somewhere else, the parts will retain their properties even if you rotate a block and rescale to turn it into a polygon. The unique properties of these parts will not leech over to anything else either. Well, fixated groups with different air friction multipliers will often have drastically miscalculated air friction, but delete the fixates and each part goes back to normal.