[math-fun] Colored edge maze

I want to amuse my kids by having them help me draw a maze in our asphalt-covered driveway (in three colors of chalk) and then having them try to solve it. The maze I have in mind is one I saw years ago. It's a square grid with colored edges and one is required to traverse the edges in the order red, white, blue, red, white, blue, ... (or whatever). Can anyone give me a link to the design of such a maze? Thanks, Jim