This is a cool picture from a series of coffee art on napkins.
My inner accountant quickly convinced me to buy one of those little espresso machines (for the price of approximately 10 tall lattes). It had a steam nozzle to heat milk, which one should clean very thoroughly after each use. I didn’t have the patience to do so. Within a few uses, an unappetizing, dark brown, organic lump developed around the nozzle. A few days later it had become unremovable, and I reverted to getting my coffee outside.
That’s right people. Timely advice to clean your steam wands.