I have what I believe to be a good design for the base of the tri-veiwer. My main reference came from a fairly straight on shot of the viewer that can be found in THIS blog post. I straightened it in photoshop a little bit, but the front face is undeniably shaped like a pyramid with a rectangular base.
Another few screen grabs show some other details.
Here's my process. I drew up my design in illustrator, then printed it out on card stock. This is the same stuff that pepakura folks use to make Iron Man and Halo armor.
Once cut out, I assembled all of the pieces as much as I could, but keeping it flat. Please note that it was about at this time I realized there was a problem with my design :)
After another iteration with the top plate, I taped it all up and here's what I got. You can see from the pics that there's a flaw in my print out, as I forgot to account for the fact that the corner triangles are set at an angle, and are not lying flat. Hence the three gaps. This has since been corrected.
I'm definitely interested in feedback if anyone has any. I've really based this off about four screen grabs, and I may very well have missed a detail or two.
Interestingly enough, I JUST realized I made a tiny error in my calculations. I was looking at the profile of my prototype, and comparing it to the profile of the Mudd capture. I realize that what I saw as the angled edge on the side of the base is a different edge on the prototype. Hard to explain without some pictures, but the punchline is that I need to modify things a bit.