Sesame Street Flashback

I'm housesitting for a few weeks for some borzoi breeder friends. Here, we leave our shoes at the door and wear soft slippers in the house.

Today, as I was passing through the living room, I noticed this: Click on photo for larger image....

And, I had a sudden deja-vu of this Sesame Street Song from my childhood. Remember this one?:

Three of these things belong together
Three of these things are kind of the same
Can you guess which one of these doesn't belong here?
Now it's time to play our game (time to play our game)!

Now I've got that Sesame Street song stuck in my head all day, no damage to my shoe, however. Let the games begin!