Use something hard to scratch indentations into the wood. A small pair of pliers or even the little dowel from the back of the frame works great.
Paint over the Vanilla with a layer of Espresso.
Dry brush Robins Egg Blue over the dry Espresso layer, wiping excess paint off the brush before applying. Leave some areas with the Espresso showing through.
Dry brush Vanilla over the Robins Egg Blue in various areas of the frame.
When everything is dry, use a sander to remove paint from the edges and corners, and go over the entire thing lightly. It’s alright if you remove a little of the paint along the way.