Intellectual excursion in math, programing, visual arts, humanities.
The site began in 1995. Got a domain xahlee.org since 2000. And since 2010, it has been split to mulitple sites:
Subcribe at Subscribe feeds
Put money in my patreon. https://www.patreon.com/xahlee
put money to bitcoin
thank you for donations. (old link, not updated)