"Pyramid" by David MacCaulay was one of my favorite books in the middle school library when I was 13.

I think the idea of canals for quarrying and transport is pretty solid. The idea of using floats to bring blocks up though? That seems kind of crazy-cakes.

As far as I'm aware, For that flotation shaft to exist, you need to be able to build a completely water tight seal. The demonstration is using what look to be acrylic pipes with some rather beefy fasteners for the gates. Now, if someone can make a rig like that with limestone, granite, and gypsum mortar, and have it not fall apart immediately, this may be a little more plausible. Also remember, that it doesn't just have to seal to get 1/3rd of the way up the pyramid, it has to seal over 61m of covered shaft containing (assuming the shaft is twice the size of the average block) about 500 tons of water. Seems unlikely to me. On the other hand, I'm not an engineer of any sort.

I also think that "why would they over engineer a simple walkway?" is kind of stupid. They were building a fucking Pyramid. They were building a tomb for a living god. They were building something that would be the tallest man made structure on earth for nearly four thousand years. The better question is "Why wouldn't they over engineer a simple walkway?"

Still, stars for effort.

Maybe insane, but I think it is the product of a runaway imagination. Someone thought they had a great hypothesis-- naive about everything else/keen on making illustrations-- just worked through to completion on a full presentation unfortunately without research or getting feedback. I saw this in January I think (4 months ago.) If they just left it there like that I hope they're alright. IIRC it's not quite finished looking, come to think, maybe they came to their senses and just put it on youtube.