Interlacing sheets of varnished different coloured leather in a cylinder shape, by Alexander Crum Brown, Edinburgh, Scotland, United Kingdom, 1912-1914. Described in the Napier Tercentenary Handbook as a knotted cylinder of gradual colours.

If the two edges of the plane above are matched with a different colour when the surface is rolled to make a cylinder, the outcome is one surface wrapped three times around. This is made clear by the graduation in colouring. Crum-Brown referred to this as ‘knotted’ as opposed to ‘locked’.