An analog stick, sometimes called a control stick, joy stick or thumbstick, is an input device for a controller (often a game controller) that is used for two-dimensional input. An analog stick is a variation of a joystick, consisting of a protrusion from the controller; input is based on the position of this protrusion in relation to the default "center" position. While digital sticks rely on single electrical connections for movement (using internal digital electrical contacts for up, down, left and right), analog sticks use continuous electrical activity running through potentiometers. The analog stick has greatly overtaken the D-pad in both prominence and usage in console video games.