It is mostly used to start up a "Cowelstone Generator".
Instructions:So, you take 6 stone blocks, a sticky piston, a redstone flare or switch, and redstone.
First you take 3 stone blocks and place them like this:
Then you take a sticky piston and a stone block and place them like this:
You place the 2 missing stone blocks like this:
Now for the redstone circuit: take a red.flare or a switch and redstone.
Place the redstone torch on the 3rd stone block upwards:
Then the Redstone:
When the stone is on the sticky piston, the motor will work.
P.S. You can also install Redstone amplifiers
Attention: If you have too many of them you can get laggs in the game.