> What colour is snow is close but you can't assume that everyone knows what snow is, let alone what colour it is. This includes both people with disabilities and in parts of the world where there is no snow...
Google will happily ask you to point out which squares contain fire hydrants. Is there a captcha that meets your standards?
Yes, I also saw the post about the fire hydrants the other day. No I was not able to confirm that fire hydrants are shown in countries in which they are not a common sight.
However, I am far from arguing in favour of reCAPTCHA. It is also an example of shit CAPTCHA that also bans people. I am often one of these people.
No there is no example of a CAPTCHA-as-a-service that I know of that I would be fine to impose on my users.
Google will happily ask you to point out which squares contain fire hydrants. Is there a captcha that meets your standards?