Minecraft wiki entry for X-ray_glitches, associated text: To set this up, start with the same setup as before, but place 2 pistons (1 at head height and one at foot height). The lower piston has a solid block in front, while the upper piston has a bottom slab. Surround yourself with additional blocks, with slabs on top, to maximize visibility. After you pull the lever, the x-ray glitch does not happen yet. Therefore, you can destroy the redstone, including the pistons, and surround yourself further. For the location that was the piston head, placing the full block is tricky, as you cannot look at a suitable surface. Instead, place the sand above where you want it to land, then place the slab as normal. When you are ready to trigger the glitch, enter sneak mode, and your eyes will lie below the top of the slab.