“…The total time taken for this calculation is about seven minutes on a 3.1 GHz PC running Linux. [ 4,24 ], [ 8,33 ], [ 12,4 ], [ 16,14 ], [ 24,11 ], [ 32,2 ] A further calculation, taking just one second, shows that no design in L is resolvable; equivalently, no semi-Latin square whose dual is in L is the superposition of Latin squares. …”