There, that's the set. Now let's see if anybody else sees what I see in these three as a set. I actually only "got" the third one initially. It wasn't until I was about to post them that I saw the first two in the same light. So you might want to "read" the set backwards from 3 to 1 if you're puzzled. Oh, and if you do see what (you think) I mean, don't give it away in your comment. Let everybody have the fun of discovering it for themselves.