Minecraft wiki entry for Piston, associated text: Notch's explanation on how the rod (a full block long when extended) fits into the piston box (whose depth is a block minus the face's thickness).[6]
Fundamental logic gates, implemented purely with pistons and redstone repeaters, clockwise from upper left: AND, OR, XOR, and NOT.
Slow clock generator with pistons and redstone.
An example of a piston-controlled waterflow.
An example of sticky piston use with glass panes.
Artwork of a Piston connected to a lever.