Underdesk mount for Wii U / PC Gamecube Controller Adapter

I have a generic adapter for connecting GameCube controllers to a PC, WIi U, or Nintendo Switch. I wanted a simple enclosure / mount that would keep the adapter under my desk or entertainment center without having to directly attach the adapter to the desk (I occasionally move it between the two, or take it with me).

This mount is a first draft--it's intended to be stuck under a desk with double-sized foam tape (the grooves on top can be used to help keep the tape hidden), and lets the adapt