This is the second less popular CGA setting, that is, green, brown (orange?), red and black - four colours often considered disappealing if mixed this way (generally not liked). My aim was to make something I've never seen being made with this CGA variant. Working with such a restriction isn't an easy thing, I have to say after trying.

It was a 45 min' sketch which I was rendering little by little (in a few days, a few min daily this time, hehe) to the effect you can see here. It doesn't differ too much from the first approach, so you may call it incomplete. But hey, sometimes it's better to leave things how they are than to overdo. It was a hard piece actually, but I'd say, an unique one. I'm really happy that some people like it.
http://pixeljoint.com/pixelart/18192.htm