Also in that article on apophenia, they brought up as an example a psychologist who wrote a paper

… describing how sidewalk cracks are vaginas and feet are penises, and the old saw about not stepping on cracks is actually a warning to stay away from the female sex organ.

That’s actually kind of interesting. I also found another very interesting piece about the origin of that saying on the website of the Committee for the Scientific Investigation of Claims of the Paranormal, in their superstitions section.

Ill-fortune is said to be the result from stepping on a crack in the pavement. Present day society usually associates the superstition behind treading on cracks to the rhyme: “Step on a crack, break your mother’s back” but the superstition actually goes back to the late 19th - early 20th Century and the racism that was prevalent in this period.

The original rhyming verse is thought to be “Step on a crack and your mother will turn black.” It was also common to think that walking on the lines in pavement would mean you would marry a negro and have a black baby. (Apparently this superstition only applied to Caucasians and because of the rampant prejudice against black people, was considered an activity to avoid.)

According to them, the saying only took on it’s present form over the last several decades. I still like the vagina interpretation though.

Anyway, for an unrelated laugh, check out these ridiculous photos on the CSICOP t-shirt order page. YOW! They need to form a Committee for the Scientific Investigation of “Getting a Clue.”