It was designed in Fusion 360 and exported with the Shaper plug-in. It’s made for Proofgrade Medium Draftboard, but I suspect any of the Medium thickness materials should work. You can get all the cuts done on two sheets of draftboard, but I had to do 4 separate passes because of alignment top to bottom. For some reason, I couldn’t get my forge to let me set up all 4 pieces on the sheet even though they should fit.
Ultimately, this is how I actually did the cuts. But do what works best for you.
But yeah, cut out 4 of each part (8 total) and then they just press-fit together. The slots are sized at 0.119 which worked really well on half my draft board but was very tight on a different sheet. Adjust as necessary (or sand it a little).
Oo, interesting idea. I would probably size the openings a lot smaller (more like that top gap) in order to stack more sheets in. (Guessing that you only have one sheet per level rather than a thick stack of wood.)