November 30, 2012

Friendship and survival

“Friendship is unnecessary, like philosophy, like art... It has no survival value; rather it is one of those things that give value to survival.” (C. S. Lewis - via University of Bucharest FB)

November 13, 2012

A nice picture with 23-fold symmetry

A nice "Paley digraph" picture - with outgoing edges from x to x+1, x+2, x+3, x+4, x+6, x+8, x+9, x+12, x+13, x+16 and x+18 (modulo 23) for x = 0,1,...,22. Generated with MAPLE.