The Twelfth Rainbow
←  Now available in paperback.
Table of Contents
1  Sprial Tilings and Integer Sequences	2
2  Exponential Spiral Tilings	9
3  N-Fold Polygonal Spirals	19
4  Triangular Tilings of a Sphere	31
5  Non-Periodic Tilings with N-Fold Symmetry	35
6  Tilings Based on Perrin’s Sequence	54
7  The Crystallographic Restriction	61
8  Aperiodic Tilings	66
9  On de Bruijn Grids and Tilings	78
10  Stochastic Rhombic Tilings	100
11  The Cube Unfolded	107
12 The Tetratorus and Other Multi-Layered Polyhedra	109
13  An Optical Illusion	118
14  Pitch and Color Recognition	120
15  Color Space, Physical Space, and Fourier Transforms	133
16  The Four Color Theorem	141
17  Octacubic Coherence and Symmetry Breaking	155
18  The Twelfth Rainbow	170