Compares two magic squares according to Frenicle's method.
Mnemonic is the old Fortran “.GT.” (for “Greater Than”)
comparison et seq.
To compare magic square a with magic square b, their
elements are compared in rowwise order: a[1,1] is compared with
b[1,1], then a[1,2] with b[1,2], up to
a[n,n]. Consider the first element that is different, say
[i,j]. Then a<b if a[i,j]<b[i,j].
The generalization to hypercubes is straightforward: comparisons are
carried out natural order.