Xah Code

This is Xah Lee's website of technical info. Math ＆ Programing. There are over 2 thousand articles. For latest articles, subscribe my blogs: Programing ◇ Web Dev ◇ Emacs ◇ Math.

Mathematics

Math reference works and essays. Full index at Xah Math. The following are popular topics.

Visual Dictionary of Special Plane Curves

A dictionary of plane curves, with history, definition, formulas, and properties. Heavily enhanced with illustrations, video animations, GeoGebra interactive applet, and Mathematica notebooks. (70+ pages)

Surface Gallery

60+ surfaces in mostly differential geometry and 30+ minimal surfaces. Moebius strip, klein bottle, cross-cap, pseudosphere, hyperboloid, minimal surfaces… (70+ pages)

Wallpaper Groups

A exposition on wallpaper groups, with illustrations of the 17 wallpaper groups and a wallpaper gallery. Technically, the derivation of all discontinuous groups of rotation and translation in the plane. (7+ pages, 100+ illustrations)

Math Graphics Gallery

A collection of mathematical images. We all know mathematics is beautiful, but did you know that math can appear beautiful too?

Includes two critical essays: Algorithmic Mathematical Art that surveys and defines the subject, and Geometry: Requirements for a Visualization System for 2020.

Great Math Programs

A annotated listing of 100+ excellent recreational math programs. You'll find polyhedra ＆ Rubic cubes, curves ＆ surfaces, fractals ＆ L-systems, tilings ＆ symmetry, game of hex ＆ game of life, go ＆ five-in-a-row, peg solitare ＆ polyominos, …

Computing ＆ its People

Tutorials, Critiques, Commentaries on aspects of the computing industry, technical and social. Siphon my knowledge into your brain; assimilate my sensibilities to your spine. Over 1k articles. Index at Computing ＆ its People.