This function was added as a wrapper to easily build up a full Quad of arbitrary data.  I use it in Double Doodle to A) Create a new Quad without wasting time setting default width/height/0/1 data on it, and then call this utility function to fill in the Quad with arb data used when drawing the Doodle Line.  I could nearly just all each of the 'setPosition' functions outside of this manually, but Quad doesn't expose a setTexCoords() option, so it made sense to allow people to be able to build up whatever shape / uv / color of quads they want from arrays of data.