I found the idea here.Except I was too impatient to find a picture, copy, get an overhead projector, trace, and then paint. Instead, I bought the white acrylic paint and free-handed it.
The contrast isn't as great as against the blue. But, the faintness of it makes it a little "sweeter" for a baby room. The whole project took me two afternoons, about 6 hrs, and $10.