The Thinker is originally a part of Rodin's "The Gates of Hell" (1880), but he became so enamored with it he later made a stand-alone version.

Of The Thinker, Auguste Rodin said,

What makes my Thinker think is that he thinks not only with the brain, his knitted brow, his flared nostrils, and pursed lips, but with every muscle of his arms, back and legs, with his clenched fist and gripping toes.

Sour Grapes (1921)
by
William Carlos Williams

The Thinker

My wife's new pink slippers
have gay pompons.
There is not a spot or a stain
on their satin toes or their sides.
All night they lie together
under her bed's edge.
Shivering I catch sight of them
and smile, in the morning.
Later I watch them
descending the stair,
hurrying through the doors
and round the table,
moving stiffly
with a shake of their gay pompons!
And I talk to them
in my secret mind
out of pure happiness.

Sources:

Public domain text taken from The Poets' Corner:
http://www.theotherpages.org/poems/wcw-sg3.html#40