Enigma 1124: Classy glass
13 March 2017
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From New Scientist #2280, 3rd March 2001 [link]
On each anniversary of its foundation my company asks a local artist to make a glass sculpture consisting of a three-by-three arrangement of squares of glass. On the first anniversary just one of the squares had to be red, the rest being blue. On the second anniversary two of the nine had to be red, the rest blue, etc. Before making the final work the artist produces scale models of all the possibilities so that we can choose the one we like best. For economy she does not make any two that look the same when rotated or turned over. So, for example, her first anniversary models were as illustrated, involving a total of just three red squares:
For our current anniversary she has again produced scale models of all the possibilities, and for these she has had to make more than one hundred small red squares of glass.
Which anniversary is it, and precisely how many small red squares does she need?