The Someday Café has a sign behind the counter that says "A fine cup of joe." After viewing it hundreds and hundreds of times, my mind saw it as "affine," which is a mathematical process of transforming images by scaling, translating, and rotating them.
Etymologically, "affine" comes from the Latin for marriage. The word "affined" is no longer in use, but once meant to be related by marriage. We still use "affinity" to mean an attraction. So graphical images that are produced via affine transformations are considered to be related to each other, differing only in size, location, or orientation.
Then came the cartoon. The coffee cup image is skewed, which results from a combination of affine transformations, perhaps a rotation, a scaling, followed by a rotation back to its original position.
Got it? Don't worry, few people do. And besides, nobody I have to explain it to thinks it's funny.
Too bad. I like it.