Symmetry abounds: the wallpaper, your chair, even your own body. Familiar types of symmetry include reflection in a line and rotation about a point. Creating a repeating pattern by translating a core segment to a new place, common in wallpaper, also counts as a symmetry, as does switching without the use of a mirror from an anticlockwise segment to one otherwise identical but oriented clockwise.
If you are interested in how medieval cathedrals came into being, and the mathematics associated with their architecture and construction, then this book is for you.
I would guess that, even a decade ago, the phrase "mathematical recreation" would have been considered a contradiction in terms. Now, in the age of compulsive Sudoku puzzlers, and an increasing canon of popular mathematics books, this descriptor has become credible.
"Oh god, I hope not," was the reaction of a student when Livio asked the title question at a lecture, and it's a reaction that's likely to be replicated by many unsuspecting bookshop browsers. But despite its frightening title, the book's appeal could not be broader.
Engineers often consider mathematics a necessary evil rather than a pursuit in itself. The author of An imaginary tale, Paul J. Nahin, is therefore a rare find.
We're in a US election year, and as is usual at such times there is some discussion about the fairness of the voting system.
If you ever have been (or wanted to be) involved in a school or office council which has to be elected by popular vote, you have a fair idea of the sort of considerations that have to be made.
Charles Lutwidge Dodgson sat in the bows of a rowing boat and heaved on the oars in time with another young man who sat in front of him.