Minimalistic shelf support

Wanted to have a minimalistic shelf support without the screws showing and without screwing the shelf itself. Very tight fit for a 15mm thick (plywood) shelf. Needs to be tight to make sure it won't move. Gap is 15.1mm and my shelf fitted perfectly. Of course it depends on the printer(settings) and wood tolerances. Don't use countersunk screws, use mushroom head screws with flat base!

Printing:

Temp: PETG 245/80 PLA+ 215/60
Speed: 100
Material: PETG (for more flexibility), but also made it in PLA+