I ran across the geekiest CAPTCHA on Adafruit Industrials blog. Thought I'd share. CAPTCHA an acronym: Completely Automated Public Turing Test to Tell Computers and Humans Apart. A good article on the invention in 2000 of some of the fist. For me, just seeing a resistor brings back a rhyme from 9th grade electronic class that runs in my head uncontrollably. B ad b oys r ape o ur y oung g irls b ut V iolet g ives w illingly A mnemonic for the resistor color code that matches the first letter of the color code, by order of increasing magnitude.