I used the ofxBox2d add-on along with the ofxDatGui addon for the purpose of controlling parts of the physics represented onscreen with elements of a GUI. Here, a rather simple toggles which turns gravity off/on allows for interaction with a joint example from the Box2D library. I chose to work with ofxDatGui to get some familiarity with an openframeworks GUI library and see how to manipulate graphics, animation, and other parameters on the fly with some user controls like sliders, buttons, toggles, etc. I used Box2D because it is a green field for this sort of manipulation, with many parameters that a person would want to test and iterate live.

Link to Github repo: https://github.com/kaurorah/iacd-gauntlet/tree/master/ofxaddons/two-addons