I changed the language to Rust+WebAssembly for speed.
Even though I was learning the new language,
I had to update it by trial and error.
The content is just an Octachoron.
About Rotate Direction:
"Rot XY" means rotation on X-Y plane.
In 3D space, it is Z-axis rotation.
"H" means the 4th direction of 4D space.
It is not "W axis", because I want to avoid confusion to scaler element of quartanion.