It's so frustrating watching some poor neophyte try to expand an image on their iPhone, isn't it? Maybe they're new to touchscreen technology. Or maybe their hand/eye coordination/intuition is just meh. No matter! Something really genius has been created for this exact situation.
Designer Juan Sanchez has come up with an origami training set of gestural interface motions; paper models to pinch, swipe, reverse-pinch(?), flick, etc.