Look at the square below containing the digits from 1 – 9.  What unique feature does the square possess?  (Suspect there could be more than one answer?)

1	2	3
8	9	4
7	6	5

SOLUTION:  All solvers noted that the increasing digits from 1 to 9 form a spiral around the outside, ending in the center square.  This is of course correct. 

ALSO, and perhaps more interesting (and one solver also noted this):  NONE of the 3 rows or 3 columns or 2 diagonals add to a sum that is repeated.  (All 8 possible directions form a different sum!)

There is a name for this phenomenon:  It is called an ‘unmagic square’.  Much more could be said here, but perhaps another time.