There's a photo of a finished mini GI on Facebook that I think is really effective! As far as I can make out, the person used purple for yellow, red for pink, green for aqua, and aqua for green. The neutrals are white. The illusion is remarkable. There's so much movement, and I see that the white squares in the sashing add to the effect. It's like dappled sunlight under trees. Fascinating! I tried linking to the photo but it didn't work -- probably not allowed?