The definition of a great puzzle is simplicity and yet that it has many permutations. John Dore has developed puzzles based on combinations of 4 colours in sectored triangles. Building on the work of great recreational mathematicians of the past, Infernal Triangles presents the puzzler with a set of 24 triangles. Readers can cut the triangles printed in the book, or download them free, to make sets. The challenges presented are to use those sets to match the shapes presented in the book. Some are simple, some are not. All can be made with the set of 24 triangles provided--and often that's the challenge!