When I got my copy of the book "Jim Henson's Designs and Doodles" back in 2001, I really enjoyed looking at Henson's inspirational sketches. But I thought some of the earlier doodles circa 1960, those on pages 10 and 11, looked familiar. After studying them, I realized why. Checking back in my old copy of Walt Kelly's "The Pogo Stepmother Goose" (1954), I found several illustrations that Henson had clearly copied into his private sketchbook. I ran this discovery by Henson archivist Karen Falk, and she readily agreed.
It's no secret that Kelly and Pogo were an early source of inspiration to Henson, and these sketches are concrete proof.
Here are Henson's drawings from "Designs and Doodles":
And here are details from Kelly's "Stepmother Goose" illustrations: