Algodoo

wow mate, i've never seen such a catapult. it may not be very strong(tough stronger that i tought it would be), but what counts is that you thinked outside of the crowd. you made something the way noone else has done it before, and thats the clue to beeing unique. its also a way to become better at phun, if you keep on doing things that have already been done by someone else, it all gets boring. keep thinking out of the crowd mate, and you might get good ofcourse it doesnt hurt looking at what other people have been doing.
for instance, my catapults frag-balls:
they consisted of two parts, the largest circle was coll-grp B and with several smaller circles inside, i made an extra ground which only coll-grp B would hit, and it was a killer, thereby making the balls explode when they contacted the ground. this way, you can make bombs or artillery shells
and just a tip on catapults or other ranged weapons, for maximum distance, the best angle to shoot at is 45 degrees, if you'd change the angle of the catapult, it might even go further than mine

good luck on phun mate, i can see you're making progress

thanks