Not the Joni Mitchell song, but a nice example of an ambigram.
I teach mathematics to new immigrants to the United States. Though the students are of high school age, some of them had not had any formal schooling in their own country. Yesterday, one student, a West African girl to whom I have been teaching basic arithmetic, was struggling with her twos and fives multiplication tables. We worked for a while with only some success, and then she turned to me brightly and said, “Ask me 379 times 13.” I was a little skeptical, but I wrote it out on the paper in front of us, the 13 beneath the 379. She looked at the example quizzically, and said, “Are you sure that’s how you write it?” So I wrote it across in a line, and she became much happier. “Ahh,” she said, “that’s 4,927.”
I thought about it for a few moments and realized she was correct. I was stunned. A minute ago she was having trouble with five times six; now she was answering this difficult multiplication problem seemingly in her head. I asked her how she knew.
She smiled at me and said, “I saw it in a movie in my country. In the movie, there was a school, and the teacher in the classroom put that example on the board. I have been waiting for someone to ask me 379 x 13 ever since!”