[Masterjun]

I think the original commenter is correct that there is a mistake in the perspective code. It seems the code calculates the linear interpolation for the grid points too late. It should be before projecting, not after.

I opened an issue ticket on the repository with a simple suggested fix and a comparison image.

https://github.com/tscircuit/simple-3d-svg/issues/14

[seveibar]

That admittedly looks a lot more correct! Thanks for digging in, i will absolutely test and submit a correction to the article (i am still concerned the straight edges are misleading here)! And thanks to the original commentor as well! I think I will try to quickly output an animated version of each subdivision level, the animation would make it a lot more clear for me!