I found an interesting post printmag.com: The mystery of the pointy S. Yes, this "S" is something I've seen scribbled by kids at school as well, and back then a wide version was popular as well due to the "Solomon" backpack with the fat "S" being ubiquitous at the time. Everyone had one (except me). If you had one, join the facebook group.
Remember in middle school how there was that pointy S that a few kids would draw? Two sets of three parallel vertical lines, and four parallel lines each at 45-degree angles? Ever wonder why there's a few kids in every class that draw it?
In the comments you'll find that people drew this pointy S everywhere around the world. Any generation. Intriguing.