General links

Specific place in the site on the left  (here)

Larger images  (also see SiteMap


Outer billiards

American Mathematical Society


Institute of Physics


NASA Jet Propulsion Lab at Cal Tech

WAV audio files from Mars rovers


Index of video , 2011 Invention challenge

Cambridge University

Plus magazine - Octonions

Richard Schwartz at Brown

Papers , polytope exchange maps

John Baez at UC Riverside

Network Theory

Foundational Questions Institute


Norwegian University of Science

Andrew Stacey

St Andrews University, Scotland

Curves index

Polygons of Durer

Cornell University

Polygons of Albrecht Durer

Outer billiards, digital filters and kicked Hamiltonians, arXiv:1206.5223

Outer billiards on Regular Polygons, arXiv:1311.6763

First Families of Regular Polygons arXiv: 1503.05536

First Families of Regular Polygons and their Mutations arXiv: 1612.09295

Cornell University Historical Math Site

Albrecht Durer paintings

Ruler and compass constructions

outer billiards ,DürersHeptagon, Dürer9-gon

Encyclopedia of Integer Sequences


Clifford Pickover

Reality Carnival

University of Manchester (U.K.)

Walking Randomly



San Jose State University

Roger Alperin (origami)

Origami site


Martin Wittenberg (twitter)

Projections from this site (see Feb 1 entry)