Construct a Magic Square
To construct n x n magic square n x n ( n odd):
1. If i is in b[r][c], then i+1 goes in b[r�][c�], where r�,c� determined as follows:
(a) try r�= r-1, if -1, then use r�=n-1.
(b) try c�= c+1, if n, then use c�= 0.
(c) if b[r�][c�] is already filled, use