The first decision should be the two colors to be used for the border/turtle main color and the background color so that the rest of the colors can be chosen to correspond. The designs are only for reference because computer designs can’t properly represent this translucent glass well enough to make color choices. I painted the edges of the glass samples I have to emulate how the glass would appear when grouted. Please still refer to the actual glass samples because even though I tried to photograph the glass colors as accurately as possible, glass doesn’t look the same in pictures.

Since the only real purple glass color is C5, all options use C5 with another color for contrast.

In the first turtle below using C5 as the background, the sections are represented by the following colors:

These three samples are using the purple C4 as the background.

In this second turtle below using C5 as the border/turtle color, the sections are represented by the following colors:

These four examples are using the purple C4 as the border/turtle main color.