Not to detract from the amazing feat the teacher and students achieved but what are "simulated vacuum tubes"?

EDIT: oh, it's really just "visual simulation" if you want to put it like that.

"Vacuum tubes were recreated using paper printed elements that match the size, spacing, and density of the originals... Cabling paths and plugboard interfaces were recreated visually and spatially so students could understand how dense, repetitive, and precise the machine was." https://www.theregister.com/2026/01/21/eniac_model_build/