A prettier shell on the seashore: the Conway criterion (Q2153985)

The article is about Conways tiles, which are tiles on a closed plane region which satisfies certain conditions called the Conway criterion. It is not very instructive to describe the criterion without diagrams, so the reader is better served looking at the article which contains several illustrative diagrams explaining many things related to the Conway criterion. The authors also discuss the Haberdasher's puzzle by Henry E. Dudeney and its connection with the Conway criterion.