I wanted a button to glue to the front of a DMG model original Gameboy that would look like BMO's triangle button. I measured the DMG buttons (1cm) and made this the same size so it would have a nicely matched look. It sits at about the same height as the A and B buttons as well.
Pretty impossible to mess up, so print using whatever settings you want.
IT IS NOT A FUNCTIONAL BUTTON. IT IS LITERALLY JUST A FLAT TRIANGLE OF PLASTIC ABOUT THE SAME SIZE AS A GAMEBOY BUTTON, LOL.
If you wanted this to be set inside the shell and appear like the rest of the buttons (THOUGH STILL NOT FUNCTIONAL AS A BUTTON) just go ahead and print it on a thicc raft, then cut away all but a few mm of it to give the triangle a ridge to sit on. Then cut a 1cm triangle into your shell with a dremel or drill + file, and then glue the print in from the inside of the shell by applying glue to the raft. Easy peasy.