Keywords: Amman-Heesch-4.svg polygon discovered by Robert Amman formed from a regular hexagon by adding projections on two of its sides and matching indentations on three sides It may be surrounded by four layers of congruent copies of itself but not five See Heesch's problem self-made originally for http //www ics uci edu/~eppstein/junkyard/heesch/ The Geometry Junkyard; also previously uploaded to en Image Amman-Heesch-4 gif 2000-04-16 David Eppstein Order-3 hexagonal tiling Files by User David Eppstein from en wikipedia Hexagonal tilings SVG geometry |