This binary counter was inspired by the idea of using physical blocks change affect others. An easy method of achieving this would be to have interlocking gears, but that would cause a gradual change from 0 to 1, as the wheels rotated. Therefore, I enlisted the help of gravity to cause the black arm to drop down into a 'do not engage the next block' state, or remain taught to spin the block.

Of course, it would be much more impressive I could get an animated clip that goes from 000 to 111, so the loop is more natural, but I couldn't manage it!