Below are some photos of paintings in process. I start with plywood, usually 2 x 2' or 4 x 4' square and sand the edges. I use straight-edges to create the initial structure. I don't actually do any measuring though-- spacing is one of my natural gifts. (I'm also really good at tracking time and buying the right amount of rice for the jar, but that doesn't apply here.) Sometimes I use numbers to keep track of what colors go where, but I don't mix colors with any formula-- I do that by eye.