This article is from the James Taylor FAQ, by Joel Risberg (firstname.lastname@example.org) with numerous contributions by others.
From Thorbjorn Nilsson (email@example.com)
Quoting JT in the 6/11/81 Rolling Stone article:
The song B.S.U.R. on Flag was inspired by the cartoons of William Steig,
who has a book out called CDB! about how to take letters and numbers and
turn them into sentences, like IMAUMBN (I am a human being) or URNNML
(You are an animal). Well, my sister and I used to play that game.