Walking on tiles
It is shown that a tiled floor provides continuous stabilizing visual information against stumbling and falling while walking. A steady walk, eyes at a nearly constant height, maintains a certain level of net optical flow in a tile's image. A stumble generates a disturbance in the net flow, which is fed back as a corrective signal to the limbs. This may explain why people with certain motoric disorders, such as those associated with Parkinson's disease, appear to be more comfortable walking on tiled floors than on untiled ones.
optical flow parkinson's disease visual feedback