This is a ratcheting device that replaces traditional shoelaces, saving the time and effort of tying your shoes. In addition to the 3D printed parts you will need some steel 0.5mm fishing line (I am using SurfStrand brand 0.5mm 7-wire braided fishing line), a few sewing pins, and two small springs (diameter < 5mm) for this project.
For your first go round I would recommend printing the pieces individually, starting with the following order:
This will let you check the fit of the pieces as they are made. The gaps between the pieces are quite small so if your printer isn't extremely well calibrated you might need to play with their scale using your slicer (or the parametric Fusion360 model) to nest all the pieces so they rotate freely without wobble.
Each unit requires one of each printed part.