Cutting Corners Collapsible Travel Tray

This is my take on a collapsible tray. You know what I mean — one of those "flat pack" things where, when you pinch the corners together, it forms a tray that you can use to hold small items. Depending on the size of the square that you start out with, you can make these as tiny or as large as you need.

I've already encountered several patterns/tutorials for these things during my online browsing over the past year and some. Oddly enough, however, none have enticed me to make one yet, likely because for such a small item, all of the patterns seemed to require a bit more work than I was prepared to do. So leave it to me to design a version that literally "cuts a corner" out of the equation, leading to the name of the project. Instead of starting with a square, I thought, why not make it a triangle?