The Fool’s Song by William Carlos Williams

I tried to put a bird in a cage.
O fool that I
For the bird was Truth.
Sing merrily, Truth: I tried to put
Truth in a cage!

And when I had the bird in the cage,
O fool that I am!
Why, it broke my pretty cage.
Sing merrily, Truth: I tried to put
Truth in a cage!

And when the bird was flown from the cage,
O fool that I am!
Why, I had nor bird nor cage.
Sing merrily, Truth: I tried to put
Truth in a cage!
Heigh-ho! Truth in a cage.

From Poets.org