Before revision: For an illustration, see URL Induced movement with stationary target A moving object appears to be moving faster when it is moving in the opposite direction to the background; it appears to be moving slower when it is moving in the same direction as the background.
After revision: For an illustration, see URL Induced movement with a moving target A moving object appears to be moving faster when it is moving in the opposite direction to the background; it appears to be moving slower when it is moving in the same direction as the background.