Out of 1,600 squares, I estimate I have 400 left. Each square is painted with a mix of 2 tube watercolors- approximately 50/50. Tube colors are arranged in a list repeated on the top and one side. This way each mix can be shown once at a deep strength and once as a pale version. A diagonal line runs through the center of the blocks. This is where the true tube colors meet. I’m eager to use this guide in my painting and have already noticed some rich mixes that I haven’t typically been using.