We tried our best, but here are some errors we’ve found. We hope you won’t find more but of course you will. Please send them to us. Thanks!
| p.0 | John Conway was born in 1937! This is a kind of sloppy error that we think he would have enjoyed. It is correct in the preface. | |
| p. 5 | I don’t know why some of these dots are missing in print, and more missing elsewhere. Should be fixed now. |  |
| p. 11 | In the answers for page 3, one of the snowflakes got the wrong signature; it’s *2. |  |
| p.78 | Can you explain the “Mirror Paradox” ? … The real toy is left -handed and its image directly across in the back of the kaleidoscope is too. | |
| p. 82 | The signature of a basketball, asked for on page 69, was omitted from the answers. It is 2*2. (If you are surprised that this is not *222, you are hardly the first, but find an actual basketball and take a look!) | |
| p.111 | A disk always has Euler characteristic $1$: the very simplest map has 1 face, 1 edge, and 1 vertex, for V-E+F= 1-1+1=1, but any map will do. | |
| p. 126 | In the text at lower right: Below we draw another way to visualize the crosscap. At below left in the figure, a Möbius band … middle. Above this, a disk has been arranged… |  |
| p. 136 | As we saw on at the bottom of page 134, when we split open a 2-fold cone… | |
| p. 140 | There are ten symmetry types that cannot be tie-dyed without cutting the fabric. The condition is incorrectly stated: the orbifold must be embeddable and there can be no cone points. | |
| p. 143 | Exercise: In Exercise 2 on page 128, you may verify… | |
| p. 143 | For example, the planar pattern at the beginning of Chapter 3 has signature 22x. Among its symmetries are two kinds of 2-fold rotation, one kind of glide reflection with a horizontal glide axis, and another kind with a vertical one. ….The two different models show the results of unzipping the orbifold along different kinds of glide axes. | |
| p. 156 | The tiling at the bottom left of the page has symmetry type 32x only if the colors are ignored. In the technical language of Chapter 19 of The Symmetries of Things the uncolored tiling is absolute. However, as a colored tiling, it is relative and has type 3322. |  |
| p.165 | …The pattern at lower left is trickier — the blue and the green squares cannot be interchanged, but polygons of the same color can be. With mirrors along the rows of green squares, the type is 3222*. | |
| p. 169 | In the illustration credits for p.45, it’s the Queensboro Bridge. |