Minecraft wiki entry for Historical_effects, associated text: The above details still apply at this point. Pistons now gain an additional distortion at this point. If it is extending parallel to the direction of travel, it will now appear shorter, and detached from the piston body slightly. At 4,194,303 blocks exactly, the texture on the arm will appear slightly squished if facing in the negative direction (as tested on only one positive axis). Beyond this point, the texture mapping will no longer be squished, but part of the arm will be inside of the head (to compensate for its detachment), which can be seen by clipping inside of it.