These three polishes are super sheer.  I had an idea to layer them over one another to see how the colors changed.  The polishes I used were OPI Calendar Girl (pink), Sea Ya Later Sailor (blue) and Sit Under the Apple Tree (green).

I tried to make each nail different, by doing the colors in different orders.  I love the green over the pink-ish because it makes a a really warm orange.  Then the blue over the pink/red makes a slight purple.

My ring finger is my favorite.  It's got a bit of a ROY G BV gradient going on.  I've got a couple other ideas for layering experiments with these polishes.  Hopefully I'll get around to them sooner or later.