In the first minute of this short video, Dick demonstrates that cyan, magenta, and yellow are the true pigment color primaries. You can mix red or blue from them, and an infinite number of other colors. Traditional dogma names red, yellow and blue as primaries, but they are not, because mixing them cannot produce green, purple, magenta or cyan, among other colors.
The last two minutes of the video demonstrate the magical variety of colors that occur when different transparencies of yellow, magenta, and cyan are gradually overlaid. This is very close to what happens when painting a watercolor using only these three colors, as Dick does.