I wrote a spatial indexing algorithm that follows the path of a recursive space-filling curve (akin to a Hilbert curve but designed to proceed diagonalwise in 3D). Good for sorting the 148 named CSS colors into a black-to-white spectrum:

observablehq.com/@pamacha/sor...

Another experiment with UMAP – nested embeddings! A spherical embedding of the scikit-learn digit dataset, along with independent embeddings for each digit. Preprocessed in Python, visualized with D3.js:

observablehq.com/@pamacha/nes...

A first pass at UMAP on a sphere! The scikit-learn digit dataset, embedded with Python, visualized with JS, packaged & deployed with Observable Framework:

pamacha.observablehq.cloud/spherical-um...