Go to a local high school. Go to a restroom, and inspect the stall walls. You’ll find all kinds of things written on the inside. “Call xxx-xxxx for a good time”, grotesque etchings, racial slurs, and sexual humor are the type of things you might find.
Go to the nearest university campus, and you’ll find much the same. Go to a local restaurant, and there will be little difference. Go practically anywhere that has even a semi-public restroom, and you’ll find similar things.
What kind of graffiti do you think I find in the stalls at $work?
Long division, carried out to 12 decimal digits.