Minecraft wiki entry for Piston, associated text: This piston clock is a simple way of repeating a circuit that goes at high speed without burning out. It does not require repeaters or redstone torches. A tutorial is available here. It requies a single sticky piston, one lever, a small amount of redstone, and some solid blocks. From the lever, the redstone has to be placed so it goes up a block, before linking up to the piston. The piston has to be placed in a way that, when it is extended, it blocks the redstone from going up the side of the block without breaking the redstone. This breaks the circuit, removing power from the piston and thus retracting it, causing the circuit to open again. The signals are too fast to affect lighting sources such as lamps and redstone torches. Doors and dispensers both work well at this speed.