Colour analysts who use this 4x4 system explain it as each season has a pure palette and to create the other 3 you add grey (toned), add white (tint) or black (shade) or keep it pure. I can look ok (meaning not dreadful) in the other Springs, soft autumn, deep Autumn and Winter... but the best colours that really make my face pop are clear, toned and warm, that cant all exist together in the other systems.