Switchboard

Switchboards are a kind of platform in Super Mario 3D Land and Super Mario 3D World. They are green and have two arrows, pointing left and right, each one on a pad. If the player steps on one of this pads, the arrow on the side they stand on will turn yellow, and the Switchboard will move over rails to the indicated direction.

Switchboards first appear in Super Mario 3D Land in World 1-3, and appear in large numbers in World 1-4, Special 3-1 and Special 5-3. If there are small blocks at the end of the rails, the platform will simply bump and stop. Rails with no blocks on the end will cause the Switchboard to fall down.

Switchboards return in Super Mario 3D World, appearing in World 3-7, Switchboard Falls and, Cosmic Cannon Cluster where they are the main mode of transportation. This time, the border around the platforms is white instead of green. They can be controlled with the touch screen on the Wii U Game Pad by touching one of the arrows. Doing this will also cause it to move in said direction even if the player is standing on the other arrow.

Trivia

 * A similarly functioning type of platform with four arrows and directions that it can move in appears in Hazy Maze Cave in Super Mario 64 and Super Mario 64 DS.
 * Another similar platform appears in New Super Mario Bros., more specifically, in World 7-2 from that game.