Re(1): Listener 4360: What a Turn-up! by IOA IP: 220.127.116.11 Posted on September 11, 2015 at 04:23:16 PM by Gerry Leversha
Sorry, I did not like this at all. The condition for 180 rotational symmetry implies that a representation of a digit must map to another representation (of the same or another digit). But it is quite clear from the samples we are given that the representation of 1 does not map to any of the ten possibilities. This is not a quibble; it is a mathematical fact. So, strictly speaking, the puzzle has no solution, as one can very soon show that there is no solution using only the digits 0,2,5,6,8 and 9.
Obviously I went on to assume that 1s were permitted and achieved the expected result. I suppose it could be argued that there is no need to place the digit representation of the 1s in the centre of each cell, but displace these so that the resulting 1 appears to be in the centre. I see that the published solution does this and assume that any solvers who placed the 'calculator displays' for 1 centrally were marked wrong. But for me this is a fatal flaw in an otherwise clever puzzle. Replies: