Why does s "-4^(1/4)" make Google think of porn?

Warning - Don't type the below search terms unless you understand that it will yield results that others may find offensive.

No idea how the first person found this bug; typo, too much time on their hands, site filter at work? But I saw over at Quora that someone stumbled on a search query bug that, for some reason, yields porn results even if safe search is turned on. The equation above, which results to "1-4" -4, has been fixed but was the genesis to the insight

In a nutshell, if you quote two search words and then negative one of them the resulting search is adult. However, it is not exactly a consistent bug, so you have to work at it.
For example this will yield porn results:
""apple 1" -apple"

But this will return nothing. (Clearly another Google oversight):
"MajorGeeks rules" -rules

With the lack of constancy it's a bit difficult to figure out exactly what is going on but our current speculation is that if you confuse Google, it thinks of porn... which may make Google a little more human than we may have thought.

Have fun thinking of some of your own, but don,t do it at work.

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