Historians like to say that the Dark Ages were passing away in much of Europe by 1500, and the Age of Reason was totally triumphant by 1700, but historians are generally wrong; their mistake here is not to count heads. For all of Western Civilization, the percentage of people still living in the Dark Ages in every meaningful respect is generally 30% to 50% of the population. [For example, 50% of the adult population in the US does not know the earth revolves around the sun, taking a year per orbit.]

In April, 2005 citizens in the Chicago area could marvel at an amazing apparition of the Virgin Mary, which used to be a standard water stain on the standard concrete side of an overpass until it got on evening TV news. Followers of such phenomena will remember the image of Jesus that appeared on a tortilla, the image of the Virgin that was found on a grilled cheese sandwich, the bun that was a dead ringer for Mother Teresa, and much, much more. If you need to impress someone, refer to this illusion as pareidolia. One of the most bizarre recent examples is discussed here.

It's my impression that the Virgin Mary is far ahead in these sweepstakes with J. H. C. a distant second. Perhaps this is because anything shaped like an upside-down "U" qualifies as the Virgin, who is generally depicted as dressing like Emperor Palpatine in the Star Wars films, while you need a bit more structure to have a J. H. C.

Those few whose memories go back as far as 1996 and Clearwater, Florida, will remember a mystic apparition of the Virgin Mary (or perhaps Darth Vader, fans disagree strongly) which appeared on the improperly installed (stressed) windows of a building. A teenager knocked out the top three windows with a slingshot in March of 2004 so this miracle of the ages is no longer drawing Dark Age tourists, but there's a new, strong contender every few months.

The phenomenon we are encountering here is of course our old friend, the "Man in the Moon" illusion. Almost any blot, burn, stain, or discoloration could be interpreted as some socially significant figure. We normally are too busy to seek such an identification in the hundreds of random patterns we encounter in every day of our lives. On the 2nd level of Painter Hall is a stunning apparition, which has existed for many years, and which I call the «Holy Chicken». I will award a prize to the first 3 people to spot it. [Contest opened January 11, 2010.]

Next illusion in the set?

The saltwater stain on the Chicago overpass was scrubbed off in May, 2005, but there's still the Virgin Mary fence post in Australia to appreciate.

Hamlet: Do you see yonder cloud that ’s almost in shape of a camel?
Polonius: By the mass, and ’t is like a camel, indeed.
Ham. Methinks it is like a weasel.
Pol. It is backed like a weasel.
Ham. Or like a whale?
Pol. Very like a whale.