This explains why in some games rocks and stone are coloured in other shades to get a good colour layer with more than 3 shades (black, grey and white).
Notable exemple exemples : [[Defender of the Crown]] with Purple rocks and stone walls... Also [[Barbarian]].
Also it is also notable that this palette has a "lot" of Blue and Green variations...it is possible to use a mode 0 screen with almost only16 pseudo Green and Blue colours (yet a bit purple for some of them).