To create transparency, a change in value is required. What if you overlapped two leaves?
This isn't the best picture, but you can see the changes in color when the circles overlap. I simply cut out a shape of another color to create the illusion of depth. I knew yellow and blue made green, so I inserted an arc of green fabric in the overlapping area. Here it is quilted:
Are they parasols? Flowers drifting along a river? Or Japanese lanterns? Intead of landing flat on the black background, they are flimsy and see-through. That's transparency. Fun, right?