Martin Gardner's article on aperiodic tiling:
Roger Penrose's Pentaplexity article on aperiodic tiling:
Steven Dworkin's article on the spectrum of aperiodic structures:
Encyclopedia of Tiling:
Summer 2006 conference on aperiodicity/sphere packing:
Summer 2006 conference on aperiodicity/phase transitions:
Winter 2006 Round Table on aperiodicity/granular matter:
Some web pages