Pokeball.

thingiverse

This Pokeball is engineered to open easily. To bring this design to life, you'll need two springs, a paper clip, and some super glue. I found it necessary to break an ordinary pen to obtain the springs required. Additionally, scaling up all parts by 50% will enhance functionality. It's also essential to sand the hinge gently with fine-grit sandpaper. Finally, use a 1/16 drill bit to create a slow-drilled hole through the hinge. These modifications will complete this project successfully.