The button is a fixed source of power controled by the player. When placed, it turns on for about one second, or ten ticks. It directly powers the block it is on, but can only be placed on walls. It also powers all other blocks adjacent to it. It's short pulse makes it good for user controled clocks, button pressing games, and other things where a lever would be unwieldy. Many people also think that it looks nicer than a lever. For this reason, some people make all-button panels. However to simulate the lever requres a T Flip-Flop, or toggle switch that toggles whenever the button is pressed.