Switchboard

Switchboards are green movable platforms in Super Mario 3D Land and Super Mario 3D World. They are divided into two pads that display arrows pointing in opposite directions. Across the middle of the Switchboard is an axle with wheels, enabling it to move on rails. If the player steps on one of its pads, the arrow on the side they stand on turns yellow and the Switchboard moves on rails in the indicated direction.

Super Mario 3D Land
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. The rails under a Switchboard may have blunt ends, making the Switchboard come to a stop once it bumps into them. However, some rails do not have these ends, and the Switchboard will simply fall off the rails if led there. The Switchboard will safely land on other rails most of the time, but in some situations it may fall into an abyss, bringing the character along with it and causing the player to lose a life. The Switchboard accelerates on inclined rails, making it more difficult to control.

Super Mario 3D World / Super Mario 3D World + Bowser's Fury
Switchboards return in Super Mario 3D World, appearing in Switchboard Falls and Cosmic Cannon Cluster as the main mode of transportation. Here, the border around the platforms is white instead of green. The character can use Switchboards to dodge Fuzzlers in the former level and Cannons in the latter. If multiple characters stand on both sides of a Switchboard at once, it will slow to a stop and remain stationary unless it is on an inclined rail. Additionally, the on the Wii U or the  button on the Nintendo Switch can be used to control Switchboards without direct interaction, as tapping one side with the cursor will cause it to move in that direction.

In the Bowser's Fury campaign of Super Mario 3D World + Bowser's Fury, Switchboards are used to traverse Mount Magmeow.

Super Smash Bros. series
Switchboards also appear in Super Smash Bros. for Nintendo 3DS in the final portion of the 3D Land stage, albeit without the arrows. They can be destroyed by Spike Pillars, which serve as stage hazards in the stage.

In the Super Smash Bros. Ultimate version of the stage, the Switchboards are redesigned to have red checker patterns on them.

Mario Party 10
The Switchboard also appears in Mario Party 10 in the minigame Bullet Bill Bullies. The solo player has to move sideways with it to dodge incoming Bullet Bills from other players.

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 in World 7-2 of New Super Mario Bros., which also exists in the code of New Super Mario Bros. Wii.