~ Early Web Links ~

The North Suburban Math League (NSML) organizes competitive math meets for Chicago-area high schools, with five competitions held throughout the school year. The site provides contest archives, meet schedules, written and oral topic lists, coach resources, and a history of NSML alumni who have earned medals at the International Mathematical Olympiad.

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.

Alex Rutar is a mathematics postdoctoral researcher specializing in fractal geometry, dynamical systems, and dimension theory, with affiliations at the University of Jyväskylä and a PhD from the University of St Andrews. His site serves as an academic hub linking to his publications, expository writing, CV, and open-source developer tools built around LaTeX and terminal utilities.

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.

Created by Robert G. Scharein, the KnotPlot Site is a visually stunning exploration of mathematical knot theory, featuring hundreds of images and animations generated by the KnotPlot software for Windows, macOS, and Linux. Visitors can browse galleries of torus knots, Celtic knots, hyperbolic knots, Brunnian links, and fractal structures, as well as download the KnotPlot program itself to visualize and manipulate knots in three and four dimensions.

Math @ CowPi offers a curated collection of math tools and resources, including interactive GeoGebra sketches, a system-of-equations solver for up to five unknowns, and a full annotated text of Edwin A. Abbott's classic novel Flatland. Visitors will also find organized math links spanning algebra, geometry, trigonometry, and calculus, making it a handy reference for students and enthusiasts alike.

The Geometry Center was a University of Minnesota research and education hub dedicated to mathematics, geometry, and visualization tools, now archived after its closure. Visitors can explore interactive Java applications, 3D geometry software like Geomview and JGV, multimedia math documents, downloadable software, and video productions covering topics from solar system models to symmetry exploration.

Pinference is an R package by PierGianLuca Porta Mana that implements probability inference for propositional logic, calculating lower and upper probability bounds for logical expressions using Hailperin's procedure. The documentation site covers the theoretical foundations connecting probability calculus to sequent calculus, with worked examples and an API reference for the inferP() function.

GoGeometry, created by Antonio Gutierrez, offers over 1600 illustrated geometry problems alongside interactive lessons and tutorials suited for both students and teachers. The site blends mathematical rigor with cultural touches, weaving in references to Incan heritage, Machu Picchu, and the golden ratio to make geometry visually engaging and globally inspired.