Snake is the common name for a video game concept where the player maneuvers a line which grows in length, with the line itself being a primary obstacle as well as walls. The concept originated in the 1976 arcade game Blockade, and the ease of implementing Snake has led to hundreds of versions for many platforms. In this early Macintosh version, there are obstacles and walls which cannot be contacted or a life is lost. The snake grows longer as it eats a dot on the screen and the player must avoid contacting the walls or any portion of the snake. The D and G keys are used to move the snake left or right. The snake must eat before the timer expires or a life is lost.