Recreations
- 141
- RJN's More Digits of Irrational Numbers
- Several million digits of e, and the square roots of 2, 3, 5, 6, 7, 8, and 10.
- 142
- Stewy's Site
- The infinitesimal is the opposite of infinity, and mathematicians still argue over its existence. This page probes into one of the weirdest numbers in mathematics.
- 143
- Timothy J. Warnock: Blog
- Dedicated to the natural order of the universe and to the irrational and logical chaos it presents.
- 144
- Triangular Numbers
- Properties of triangular numbers including reversible, happy, harshad, highly composite, deficient, abundant ones.
- 146
- World of Numbers
- Includes a collection of randomly gathered numbers, curios, puzzles, palindromes and primes.
- 148
- Artlandia SymmetryWorks
- Adobe Illustrator plug-in that automates creation of surface designs and ornaments based on seventeen wallpaper groups. On-line purchase.
- 149
- Catalogue of Isohedral Tilings
- From the article "One Corona is Enough for the Euclidean Plane" by Doris Schattschneider and Nikolai Dolbilin.
- 150
- Chaos Tiles
- This chaotic tiling consists of two equilateral pentagons, with angles (80, 160, 60, 140, 100) and (40, 200, 60, 100, 140). Sets are for sale.
- 153
- Hans Kuiper
- Hans Kuiper's work. Tessellations and optical art. Also tessellation software with the 17 wallpaper groups.
- 155
- Java Kali
- A program for drawing symmetrical patterns based on any of the 17 wallpaper groups, as well as several frieze and rosette groups.