Summary: The article explains how to create spinning diagrams using HTML and CSS without JavaScript or animated image formats. The author demonstrates how to create a spinning cube with letters at each vertex and how to keep the letters facing forwards while the cube spins. The article includes HTML and CSS code snippets and animations to illustrate the process. The author notes that the spinning and un-spinning works well on mobile browsers and mentions that the original math thing involved embedding the diagrams in LaTeX and generating their geometries using a Python script.