A:= [[ 4, 2, 6, 1, 5, 3, -7], 
     [-2, 4,-5, 1, 3, 6,  7], 
     [-6, 7, 3, 4, 5,-1,  2], 
     [-5, 2, 6, 1,-7, 4, -3], 
     [ 2, 1,-7,-6,-3, 4, -5], 
     [ 3, 1, 4, 5, 7, 6, -2], 
     [-7, 4, 1,-5, 6, 3, -2], 
     [ 5, 1, 2, 3, 4, 7, -6]]: