The design looks simple and requires relatively few parts. The single axle accomplishes the real work of winding the shoe laces taut. The genius of this contraption, I think, shines in how the powered components—Power Functions L-Motor, IR Receiver, and AAA Battery Box—wrap snugly around the sides of the shoe. The transfer of power bears attention, as the machine uses a series of gears, including a worm gear, to direct the twisting motion from the vertically-oriented L-Motor to the horizontal axle.
In case you’re wondering: yes, the contraption works! You can watch the self-lacing shoe in action in this YouTube clip: