Does this indicate punctuated equilibrium for tapping? The Nokia 5500 "...uses the built-in sensor to control some of the phone functions by… tapping. For example to skip to the next song just tap it twice on the right side. To listen the previous song, tap it twice on the left side. No need for dedicated buttons."

And at the same time, FP JackJack sends me this lovely video of tilt sensors tied into Exposé.