LaTeX Coffee Stains (2012)

hanno-rein.de

It's amazing how much of our modern world originated with Bell Labs:

"One source inside Lucent says that the logo is a Zen Buddhist symbol for "eternal truth", the Enso, turned 90 degrees and modified"

...now it's bothering me, how do you tell if a coffee stain has been turned 90 degrees?

The tell-tell is the isolated drip from the coffee mug handle.