There are many interesting facts in this book which I didn't know, and I try to keep up with elementary geometry. One is an asymmetrical figure containing a point such that every line through it divides the figure's perimeter in half (page 30). Another is the answer to the question "Given a square made of equal rods hinged at their ends, what is the minimum number of additional rods, of the same length and hinged at their ends, are needed to make the square rigid (in that plane)? The answer is 19, more than I would have guessed. There is also at least one theorem I needed as a reference in a paper which I couldn't find anywhere else. (Of course it's hard to search for a geometry theorem because you never know how to describe it.) In fact right now I can't remember what it is, or (needless to say) find it in this book! I recommend it, but there are very few references to the professional literature. I'd be reluctant to cite this book in a paper, because it's a dead end, and the reader would not know where to find more information. Steve Gray
Do people know this book, "The Penguin Dictionary of Curious and Interesting Geometry" by David Wells (1992)?
(David Wells also wrote the "Penguin Dictionary of Curious and Interesting Numbers", which I've heard is also good.)
I have heard of the geometry one but not seen it. I have two editions of the second one, and it is a lot of fun.
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