Minecraft wiki entry for Clock, associated text: Design G is the simplest design and can be used to create rapid clocks. However, it is not controllable, so the only way to stop such a circuit, without adding additional parts, is to break one component (one redstone wire is recommended). Place a block of redstone on a sticky piston, then lay down redstone so that the block powers the piston. Then, once the piston is powered and moves the block, the redstone current stops, pulling the block back to the original position, which causes the block to power the wire again, and so on. This clock creates a 0-tick pulse every 3-gameticks.