I was sitting in a talk today when something made me think of how we represent colors in terms of red, green, and blue intensities. We often illustrate how these components mix together with a Venn diagram of three circles. The intersection of red and green is yellow, the intersection of green and blue is cyan, and the intersection of blue and red is magenta. The intersection of all is white.
For someone new to additive color, this diagram of circles presents too much information at once. So, instead of listening to the speaker, I thought about ways to simplify the illustration. Here’s a first attempt, in which we consider only the combination of all three intensities: