One difficulty with the "work it backwards" method is that a mistake made in the arithmetic at any stage destroys all the "niceness" of the matrix, with disas trous results; and such mistakes are likely to occur when done by hand. The method presented here requires only the selection and multiplication of two matrices. Even this multiplication is prone to error if done by hand, but computer software and hand calculators can take over this task and reduce the likelihood of error. We are free to think about the design of the problem, and can generate matrices easily and accurately