Make it more difficult for bots, by alternating what to ask for?

Hi, What about alternating the questions, and instead of always two words.... ask for only letters in one or more colours, from the know word, only numbers, only small characters, n subset of the words and so on?! - Vetle -- You received this message because you are subscribed to the Google Groups "reCAPTCHA" group. To unsubscribe from this group and stop receiving emails from it, send an email to recaptcha+unsubscribe@googlegroups.com. To post to this group, send email to recaptcha@googlegroups.com. Visit this group at http://groups.google.com/group/recaptcha. For more options, visit https://groups.google.com/groups/opt_out.