Growing up, there was a giant maple tree across the street from our house, and it had a small, rounded area of bark missing right at the base, forming a recessed, smooth surface. I always thought it looked like a small door, and I imagined it was the secret door of an elevator for the squirrels. I frequently watched it to see if I could catch any rodents riding up or down, but, alas, I never did. But that never stopped me from believing all kinds of things were possible; and even if some things would never happen, it was always fun to think that they would. And I still do!