mmcirvin | Movies they constantly showed us when it was raining too hard to go out for recess

Found in the course of a discussion on

james_nicoll's LJ concerning The Red Balloon, which was definitely another one:

Robert McCloskey's Homer Price, in "The Doughnuts" (1963):

http://www.youtube.com/watch?v=5HowpkY-Aro
http://www.youtube.com/watch?v=6uU0N5jBU3Y
http://www.youtube.com/watch?v=IB1Mca6K6p8

"Caterpillar", apparently a product of Kresleny Film of Prague (possibly 1971):

http://www.youtube.com/watch?v=offeqj7OOsQ
http://www.youtube.com/watch?v=S1M6o-teA10

This second one was hellaciously hard to find, because of the much more famous 1944 Cary Grant film Once Upon A Time which had essentially the same subject.

Edit: The caterpillar movie was apparently made by famed Czech animator Zdeněk Miler in 1967, under the title Sametka (The Velvet Caterpillar):

http://en.wikipedia.org/wiki/Zden%C4%9Bk_Miler
http://accelerateddecrepitude.blogspot.com/2011/11/caterpillar.html

And it and Once Upon A Time are supposedly based on the same story, a radio play by American writer Norman Corwin called My Friend Curly. The Miler film omits most of the plot complications, and works as a simple, gentle meditation on fame and ephemerality. I also wonder if the Cary Grant film partially inspired the classic Warner Brothers cartoon "One Froggy Evening".