RGB

This week, the RuneScape update was Capes of Distinction, and many players thought that the color order of those capes followed no logical pattern.

This is the order of the 10's capes:

Consider the volume of a cube:

Where the Cartesian coordinates (with range x;y;z at 1;1;1) are in a Euclidean space. In the electronic color spectrum, the origin (0,0,0) is the color black; this is because there is no color contribution from Red/Green/Blue. On the other hand, 1,1,1 is white, due to full contribution from all colors.

If we let X be the intensity of red, Y the intensity of blue, and Z the intensity of green, then as we fix X and Y at 0, by increasing Z, color becomes more green. If we start at 0,0,1, and end at 0,1,0, then you would get the sequence of colors as on the capes:

To skip all the Calculus jargon, the 10's cape starts at Full Green, then by adding and taking away contributions from Red and Blue, we get the color order.