Raspberry Pi 3B+ Mountable Case Holder

For use with the Raspberry Pi 3 B+ Case here : https://www.thingiverse.com/thing:2967602

Based on the design here: https://www.thingiverse.com/thing:3870606

I remodeled it in [OnShape](https://cad.onshape.com/documents/07de2fb57bdddace60e237c0/w/32cea0e5f7b1d95af7a7b1b5/e/4b07d5bd37a0c994a9bf3eab), and modified it to simply use two countersink flat-head screws so that it can be mounted to nearly any surface