Ha, so Shades informed me I was missing a few WIP images on this one. I wasn't planning to do a step by step on the design... but I did take a few photos along the way just for my own reference. I'll be doing this design in a few more places later on, so I wanted to have a reminder when I came back to it. First, I marked off a series of equally spaced dots in a grid pattern. I took a scrap of paper and marked off the distance so the spacing would be consistent. These dots show me where the lines cross and where the red circles will go. I then painted thin diagonal lines connecting the dots. Following that, I went back over these lines to thicken them up, straighten them where need by, and get the sizing as consistent as possible. From there, I went back in with the white background color and painted lines perpendicular to the main ones in order to create the rectangles and squares.
Next I painted circles where the lines crossed. As before, I then went in with the background color and painted perpendicular lines to create the divisions. I then took a orange-ish red color and painted over the remaining dots to create the circles.
I then painted a thin circle followed by a thick circle around the red dots. By the way, there were plenty of mistakes at this stage (and previous ones). I was often using the background color to clean up lines that went off target or were too thick.
I then used thin white lines to divide up the red circles and the lines around them. I painted three lines for the small details in the larger circles (where the main lines cross) and added a white dot at the center of the squares. The key things are (1) to measure beforehand and place those guide dots so the spacing is consistent and (2) to go slow and just take it one part at a time.
Yesterday I did a little more work on the figure. I increased the highlights on some of the thin purple details to push the contrast. I also worked on the chest armor, finishing the sections over his shoulder and then on the top of his back. There's a bit more design work there. Unfortunately it will be mostly covered up by the rest of the helmet and his shoulder armor... but you will still be able to see it from one or two angles, so it had to be done.