As promised, here's a picture of the palette box. It uses three rows of plastic Prang kids' watercolor pans, emptied and refilled with tube colors -- some student grade, some artist grade. They just happened to fit perfectly into the aluminum palette box! (Yes, for some reason I didn't have alizarin crimson in a tube, so I inserted a Cotman half-pan in there for that color and the white for the time being.)