Enigma 1520: Just pondering
5 September 2012
Posted by on
From New Scientist #2682, 15th November 2008 [link]
Around the edge of the rectangular fish pond in Joe’s back garden is a path two-paving-slabs wide. The square slabs are coloured light brown, grey or light green. Joe has arranged them so that the pattern of colours of any square of four slabs is unique, however viewed. If Joe had needed to make the path any longer, then colour patterns would have had to be repeated.
How many slabs make up the path?