Rambo Tribble writes: As reported by the BBC, Rio de Janerio has initiated a project embedding mosaic QR codes in the city's walkways. The codes are intended to provide access to information for tourists. I imagine they will also provide access to hackers with little more than a magic marker.
Today's scientific question is: What in the world is electricity?
And where does it go after it leaves the toaster?
-- Dave Barry, "What is Electricity?"