captcha is a catch 22
I saw this as a captcha question on a website today: “Number of arms you have + the highest prime below 10″. The user is supposed to answer the question in order to submit the form. My point is this is too difficult. Unless everyone that will visit your site knows the definition of a prime number, its a bad idea. I’d rather have some crud get past the captcha instead of turn users away because its too hard for them to figure out.
Heck why not ask “A train is traveling from point A to point B that is 45 miles apart; the train travels at a constant speed of 15 mph; how many minutes will the train take to make the trip assuming there are no stops along the way?”. People hate word problems!
I’ve used “how much is x + y” where x and y are both in the range 0 to 20. This is pretty simple math.
