MP Select Mini Shelf

If you want to print with anything other than PLA, you need your printer bed to stay warm. For the MP Select Mini, that means some kind of enclosure to keep the ambient air out.

I found this excellent tutorial for creating an enclosure. Luckily, it is designed in a way that will not cause overheating for the electrical components:
https://www.instructables.com/id/MP-Select-Mini-3D-Printer-Enclosure/

But it is missing something to keep the box from falling over. The author suggests creatin