The catapult was one of the first widgets I made and it was done so early mainly as a proof of concept. I considered it one of the more complicated moveable widgets in the game and wanted to make sure it worked!
While utilizing the Hinge Joint in the Newton physics engine, it also had to have a compound collision object in the form of the cup and arm of the catapult. Something for the marble to nestle itself into before being vaulted to its destination.
The catapult is activated by the marble touching the cup/arm of the widget. Once this is done there is a 4 second delay before the catapult goes off, with or without the marble in the cup.
There are plans for having 3 strengths of catapults. One will vault you over 15 or so tiles, another will go 30 tiles, and the final will go 45 tiles, which is basically across the entire map! I think each catapult will be color-coded, or at least textured differently, so that players can recognize them immediately.