Minecraft wiki entry for Transmission, associated text: Variation (Circular Staircase): By turning 90 degrees in the same direction each time the wire goes up a block, a "circular" staircase can be created in a 2×2 footprint. This variation is 2-wide tileable in both horizontal directions as long as the rotation direction is alternated in each direction (clockwise, anticlockwise, clockwise, etc.), or 2×4 alternating tileable with repeaters.