Compact Twin-Stand Shoe Rack

This is my attempt to make a stand that would accommodate a pair of shoes in a vertical stacking to minimize wasted space and improve the organized look and feel of a house (in that department). I printed this on a Prusa Mk3 and, even if the upper shoe ended up touching the lower shoe, I decided this is still a good arrangement but your mileage might vary.

I have added a STL for a similar design that adds a lip to catch on the shelf it sits on (it can accommodate a 20mm thick shelf) because I