FYI: this is a cool hack and very impressive, but ... don't do this. That fact that it runs doesn't make it a good idea. Like running DOOM in Excel (https://github.com/Pranshul-Thakur/DOOM-in-excel) or making a DIV for every pixel and rendering by changing colors of divs https://news.ycombinator.com/item?id=46409359

Use 3D CSS to enhance a 2D page with some flair. But be aware, 3D CSS, it's trying to solve things that most realtime 3D rendering does not, like intersecting planes need to be subdivided in order to correctly handle transparency. This means 3D CSS has an O(N^2) or worse type of issue vs rendering yourself using WebGL or WebGPU where you'd avoid those issues. This demo probably does not intersect any planes but the browser itself has to check for those intersections anyway. TL;DR: If you're going to make a 3D web game use WebGL or WebGPU, not 3D CSS

Very cool demo though!