Here's another early sequence, in which Linus confounds Charlie Brown by blowing balloons into cubes. I've joked about Linus having uncanny powers, but how else can you explain this?
At least you can stack them neatly this way.
Look at Lucy's look of horror in the second panel. This strip makes it a little more clear what Schulz is getting at with this sequence. Although blowing up balloons into squares is a marvelous skill, Charlie Brown seems to think it's something wrong somehow, and Lucy thinks it'll bring dishonor to her house. I guess people put more importance into balloon-inflating style back in 1954.
Even if he tries to blow it up into a rough sphere, it comes out square. This could be taken as a metaphor for something I suppose. Actually, multiple somethings.
What would happen if you gave Linus an innertube to blow up?
"Hey! Come back with my pagan idol of music!" "Take it easy, I'm just replacing it with a good, honest Christian symbol! Er, that used to be an element of nature-worship. Merry Christmas!"
We'll have more of Charlie Brown and Schroeder and Christmas next time....