I've seen this done before, but have never done one myself. I decided to give it a go, when I saw Dylan's one, looked very satisfying. i only have 25 different colours, mostly Pebeo's half pans, though I have two pans that I cured from Windsor & Newton tubes. Doing this colour swatch made me realise that I like the colours produced by mixing the Phtalocyanine green with the blues. I also liked the mixes created with the mauve. However, the colours that came from mixing with orange didn't excite me at all! The Payne's grey mixes created nice subdued colours that would be lovely for landscapes.