Angles in key patterns

This large drawing by George Bain is a study based on the key patterned panel on the shaft of the Nigg cross-slab. Both drawings use exactly the same design of 3 by 10 repeats. But they are different sizes because the angle of the diagonal is not the same. That on the right is 45 degrees and that on the left is 50 degrees.

Bain must have seen that the Pictish sculptor’s key pattern is not set at 45 degrees and wondered why. He knew that the sculptor had the proportions of the Nigg panel that needed to be infilled. So the artist must then have changed the angle of the diagonal of the key pattern to make it fit. We think this poster neatly illustrates the different outcomes. It shows what happens when alternative geometries are applied to key pattern.