Today’s birthdays:
E. T. Bell and G. H. Hardy.
I added a paragraph today to the diamond theorem page:
“Some of the patterns resulting from the action of G on D have been known for thousands of years. (See Jablan, Symmetry and Ornament, Ch. 2.6.) It is perhaps surprising that the patterns’ interrelationships and symmetries can be explained fully only by using mathematics discovered just recently (relative to the patterns’ age)– in particular, the theory of automorphism groups of finite geometries.”
This blend of mathematical history and mathematics proper seems not inappropriate for a birth date shared by a mathematical historian (Bell) and a pure mathematician (Hardy).