It seems like there are two cases where this makes a difference: 1) Reading rules written about one color set, and mentally translating. I think any reasonable mapping is equivalent here; you've just got to keep it in mind. 2) As a player who knows a game with one color set, looking at a position in the other and just "seeing" it. Here, I strongly prefer Andy's mapping. If I look at a Homeworlds position in Xeno colors and tell my brain to find the Yellow peices (or Red or Green or Blue), it finds the right ones. I can put Cyan just as easily with blue or green. It's in between, both conceptually, and by my subjective judgment looking at the pieces. I can't see anything but orange making intuitive sense as red, nor purple making sense as anything but blue. Clear=Yellow is a bit arbitrary in the abstract, but looking at the pieces it works particularly well: yellow is by far the weakest and clearest. Obviously this is highly subjective. My ability to see cyan as green may be due to having thought of it more than most. I developed a fondness for the color at a young age when I discovered it was the perfect explanation/justification for the unusual way my family pronounces our last name. - Rob "Rhymes with Cyan" Bryan