Generation of a frequency square orthogonal to a 10 x 10 Latin square

In general it is a difficult if not impossible task to find a latin square orthogonal to a given latin square. Because of a practical problem it was required to find a frequency square orthogonal to a given latin square. We describe a computer approach which was successful in finding a (4,23) frequency square orthogonal to a given 10 x 10 latin square.