Updates to Chapter 13, "Dodecagons and Dodecagrams",
in Ernest Irving Freese's Geometric Transformations: the Man, the Manuscript, the Magnificent Dissections!,
by Greg N. Frederickson

Typo on page 126

In the last full paragraph of page 126, we need to say 'we need' rather than 'we needs'.

Harry Lindgren's dissection of two dodecagons to one is translational

Harry Lindgren's dissection of two dodecagons to one in Figure I117 is translational, as readers can easily verify! How beautiful is that?

Figure I126 is suitably translational

I neglected to state that when suitably arranged, the dissection of six squares to a dodecagon in Figure I126 is translational.

Translational dissection of a dodecagram to a hexagon

It is possible to modify Freese's dissection of the dodecagram {12/2} to a regular hexagon (in Plate 133) to reduce the number of pieces from 15 to 12 and still have it be translational. But Lindgren [1964] had a 10-piece dissection that is translational. The 8-piece dissection that I gave in Figure 133 is not translational.


Copyright 2018, Greg N. Frederickson.
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Last updated November 12, 2018.