Inspired by a tweet from 🐦 @SteveStuWill here's a CSS version of the Stepping Feet 👣 illusion.Both rectangles are moving steadily together, but they appear out of sync and in a stepping motion. Fade in a solid background and their steady movement can be seen. Give me a shout at 🐦 @rowan_m with any comments, feel free to remix and modify with that little fish button over there 🎏↗️