This was a design for someone who's been making custom game case artwork for some time and wanted to try displaying Nintendo Switch game cartridges in audio cassette cases with custom printed J-cards. Getting all the details just right took many iterations. Other people's designs for cartridge holders are usually friction fit and will damage the cartridges over time, so we wanted something spring loaded like the official Nintendo cases. Designing an integral mechanism that could be 3D printed in place took trial and error. Tuning the overall shape to fit nicely into the cassette cases while still looking aesthetically pleasing and being reliably printable also took patience. In the end, these are very friendly to 3D printing, look great, and the person making the cassette cases has sold quite a few with my prints!