Algodoo

ask if you want to use this.
if I say yes please give credit,
exept for geomarble, all he has to do is give credit
this will probably be updated in the future.
see you soon in a big way

edit: I added gravity pads

edit2: I added a rainbow marble

edit3: I added a rainbow track

edit4: I added a foolproof marker, 10 brownie points to the
first person to figure it out. (please don't comment if you are not
100% sure you know)