How about making HSR's - kinda. That is break the design down into rectangles. Some will be the plain colors and some will be combined so that 1/2 is one color and 1/2 is another.
Take 2 rectangles same size, right sides together, mark a diagonal, sew 1/4" each side, cut, and press. You may want to play around with size on scrap fabric first to see what size you want the rectangles. You could use the graph paper to figure it out too.