This heel design allows one to customize their own straps. Ideally I would like the parts to be able to interlock with each other, but at the moment the shoe components need to be glued with a strong adhesive to work. The 3d printed shoe itself, with the epoxy I used is pretty sturdy, but please be sure test it out and use at your own risk if you plan to actually wear the shoes.
The shoes were designed for a 3d printed gown. You can find more info on the project here: http://www.thingiverse.com/thing:1664748