Question: Can buttons be held? (Can long-tap of center give the context menu?) or will we need to use transitions for such things?
Though I guess "Center->Up" works.
Also, I realized my math is poor, we have a lot more than 21, since i assume "Center->Up" can be handled separately from "Up->Center". For some silly reason I just thought of them as being a single transition per interface, not two. So we actually have 9 press areas plus 24 transitions. Though I think in many cases we'll want duplication (for example, Center->Up, and Bottom->Center could do the same think, so they just need to make an upward motion in the general area of the center of the screen).