Originally created in 2004, CirculaFloor is a continually improved system of four robotic floor tiles, designed to allow an 'infinite treadmill' in VR. Wherever you put a foot, the four tiles work as swarm robots to ensure there's a tile under that foot when it lands. Walk as far as you like, and you will remain in the exact same place as you started. Stride out in any direction, and the floor will adapt, moving with you. At least, that is the theory.

Created out of a collaboration between the University of Tsukuba and ATR Media Information Research Labs in Japan, CirculaFloor has yet to take off commercially, even five years later. However, research on them never abated.

CitculaFloor consists of four independent robot units, each outfitted with ultra-sound sensors that keep track of the floor section positions, and magnetic sensors that keep track of the motion of a user's feet. The floor moves in the opposite direction from the user so that the motion of each step is cancelled and the user's position remains fixed in the physical world.

Understandably this backwards movement takes a little getting used to, without losing one's sense of balance. Thankfully, the units do move somewhat slowly, so the sensation is not as acute as it might possibly have been. Unfortunately, this also means that a normal walking pace, never mind brisk walking or running, is impossible, as the units would never react in time.

Still, slow pace aside, each unit's upper plate in current versions is pneumatic, meaning it can raise or lower relative to other units, to simulate walking up or down hill, or even uneven ground.