December 8, 1952: Charlie Brown changes his shirt

It is rather a long time to go on wearing the same shirt. But the other characters have their own distinctive looks, including Violet, so it's really unfair to pick on the kid for this.

I wonder what it was that caused Schulz to decide on that distinctive zig-zag pattern, which is not a style of shirt that I am aware of as ever being popular, or at least not other than in the sense of referencing Peanuts.

April 12, 1951: More shirt stuff

More playing around with Charlie Brown's shirt. I like how it's Snoopy who's offended by Patty's confusion.

April 11, 1951: "This is an exclusive number!"

Charles Schulz must have come up with Charlie Brown's "Crayola shirt," as I call it, as a way to make the character visually distinct from the others.  It would not be overstating things to say that it is known the world over.

Snoopy edges still closer to humanity here.  Notice that he has no thought balloons in these early strips.  I might be wrong here, but I seem to remember that Peanuts was the first strip that used them to present a way for unspeaking animals to kinda-sorta talk.

December 21, 1950: Tick tock

I've actually done this thing, with the hands, in real life.  I believe the joke here, which is a little subtle, is that Charlie Brown doesn't know how to tell time.

This strip is notable for, I believe, being the origins of Charlie Brown's distinctive zig-zag "Crayola" shirt.  (hangashore pointed it out in the Metafilter thread first.)