Three blocks, red, white and blue are shown. They are placed into a thin tube one at a time, in the following order: red, white and blue. But when the blocks spill out of the other end of the tube, they've managed to change themselves around. Now they're blue, red and white. This merry mix-up of colors happens over and over again, to the delight of the spectators. No sleight of hand - incredibly easy to do.