At ABC Wednesday, the letter for the day is R, and my contribution is roof tile - more specifically, ornate old Japanese kawara roof tiles.
These black clay ceramic tiles were (and still are) used on traditional homes and temples and age beautifully. More elaborate structures would include ornamental figures.
A typical roof tile will have some kind of design feature that may or may not also serve as an amulet. The terminal decoration is called onigawara or ridge end tiles, One popular design is the swirling eddy, as it was believed to ward against fire. I've shown you the swirling eddy before and there are a few more here (2, 3, 4 and 6), as well as other designs (1, 5 and 7).
These decorative roof details were all photographed in the Kansai region of Japan.