When a sticky piston is activated pushing another piston upwards, the piston being pushed flickers when the movement up or down stops.

How to recreate:
1 Open a creative world on Kindle Fire HD
2 Place a sticky piston pointing upwards, place another sticky piston on top and another sticky piston on stop of that, all facing upwards.
3 Connect the bottom sticky piston to a lever using redstone dust.
4 Flick the lever.

See video clip attached.