Catapults anyone?

[jburstein]

earlier this year I ruled out catapult bots as physically impossible (of the very close equivlant of, unless you can build a massless arm connected to 4 motors through a frictionless axle...

You haven't heard of a thing called a spring have you? If you need the power of four motors then maybe you'd do better having one motor store energy, that way you don't burden yourself weight/power requirements of 4 motors and the accompanying transmission.