About the Teeth of Sharks
The thing about a shark is—teeth,
One row above, one row beneath.
Now take a close look. Do you find
It has another row behind?
Still closer—here, I’ll hold your hat:
Has it a third row behind that?
Now look in and… Look out! Oh my,
I’ll never know now! Well, goodbye.
John Ciardi (1916 – 1986)