Thanks Replicant, that looks a good page as it has visuals on it and you can actually see what it means rather than trying to work out what its supposed to look like. :)

Tools:- Win10, Dell XPS8900, ZBrush, Marvelous Designer 11, Hex 2, PSP8. PSP 2019 Ultimate, DAZ Studio, Affinity Photo, Affinity Designer, Filterforge 11, flowscape,  Classic UVMapper, and several headache tablets.