Mathematics
51 sites
http://aleph0.clarku.edu/~djoyce/java/compass
David E. Joyce of Clark University presents a detailed mathematical exploration of compass-only geometric constructions, proving that a straightedge is unnecessary for any Euclidean construction. The site covers circle inversion, stereographic projection, inversive geometry, and involutory quandles, drawing on the historical work of Mohr and Mascheroni.
http://wasan.jp/english
Created by Hiroshi Kotera, this site documents Sangaku, the beautiful geometric theorems that Japanese scholars of all social classes inscribed on wooden tablets and dedicated to shrines and temples during the Edo period. It offers images of surviving Sangaku tablets and serves as a rare English-language window into this uniquely Japanese mathematical tradition dating back to 1996.
http://mathpuzzle.com/loyd
Ed Pegg Jr's digitized archive of Sam Loyd's 1914 'Cyclopedia of 5000 Puzzles, Tricks, and Conundrums' presents the classic puzzle book as a complete set of scanned page images freely available for download. This rare public-domain release preserves one of the most celebrated puzzle collections in mathematical history, making it an invaluable resource for recreational mathematics enthusiasts.
https://math.ucr.edu/home/baez
John Baez is a mathematical physicist and emeritus professor at UC Riverside whose sprawling personal site features decades of expository writing on math and physics, including his long-running column 'This Week's Finds in Mathematical Physics.' Visitors can explore course notes, research papers, talks on topics from category theory to the Standard Model, and accessible blog posts bridging cutting-edge science with public engagement.
https://ncatlab.org/nlab/show/HomePage
The nLab is a collaborative wiki covering advanced mathematics, physics, and philosophy with a strong emphasis on category theory, homotopy theory, topos theory, and their connections to theoretical physics. It serves as an encyclopedic reference for researchers and students working at the intersection of higher mathematics and mathematical physics, offering thousands of deeply interlinked articles.
https://sprott.physics.wisc.edu/pickover/home.htm
The personal homepage of prolific author and inventor Clifford A. Pickover, featuring links to his 50+ books spanning fractals, chaos, black holes, the fourth dimension, and the mathematics of reality. With 800 patents, a sprawling collection of puzzles, art, and cosmic questions, this site is a portal into the mind of one of science's most imaginative popularizers.
https://sprott.physics.wisc.edu/FRACTALS.HTM
Julien C. Sprott's Fractal Gallery is a sprawling collection of computer-generated fractal artwork, featuring a daily auto-updated fractal derived from strange attractor algorithms described in his book 'Strange Attractors: Creating Patterns in Chaos'. Visitors can browse thousands of downloadable images spanning Julia sets, Mandelbrot sets, 3D anaglyphs, tilings, and animations, plus a Java applet that generates new fractals every five seconds.
https://home.adelphi.edu/~stemkoski/mathematrix/index.html
Mathematrix, created by Lee Stemkoski at Adelphi University, explores the playful and lesser-known side of mathematics through topics like polyominoes, Rubik's Cube, fractals, Conway's Game of Life, and higher dimensions. Accessible to curious minds at any level, the site blends mathematical art, humor, poetry, and hands-on puzzles to make recreational math genuinely entertaining.
http://math2.org/
Math2.org is a comprehensive math reference site offering organized tables, formulas, and identities covering everything from basic arithmetic to calculus, linear algebra, and Fourier transforms. Available in both English and Spanish, it also features a message board for math questions and links to other top math resources on the web.
https://khleedril.org/blog
Dale Mellor is a scientific computer programmer, mathematician, and physicist who writes accessible math explainers like his 'Baby Steps for Adults' series alongside posts about science fiction, Star Trek, fine art, and daily life. The blog covers a genuinely eclectic range of intellectual interests, with mathematics and computing forming the clear backbone of the content.