|Directions: Cut off a piece of pipe about 3 or 4 inches long.
Write an "X" near one end and an "O" near the other with a black magic marker.
On a smooth, hard surface, start the pipe spinning by pressing down near one end so that the pipe flies forward as your finger snaps down on the table.
Note that if the X is visible then the O isn't and vice verse. Can you figure out why?
If you need some help figuring out how this works, press HERE
Also, check out the Exploratorium page on this topic.
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