One-Way Wall

A One-Way Wall is an object found in Super Mario Maker, Super Mario Maker for Nintendo 3DS, and Super Mario Maker 2. They are available in all game styles except Super Mario Maker 2's Super Mario 3D World style. Similar to the Flippers from the Yoshi's Island games, once Mario passes through the gate, he cannot go back through it from the other side. When pointed upwards, One-Way Walls act similarly to semisolid platforms, and when pointed downwards, they act similarly to Hidden Blocks. A One-Way Wall is the size of four regular blocks, and the arrow imprinted on it indicates the direction in which Mario can enter.

One-Way Walls can be used in conjunction with Warp Pipes and terrain to recreate one-way pipes found in several Super Mario games, except in Super Mario Maker 2's Super Mario 3D World style due to their absence.