abhijit·19년 전·discusssimple arithmetic ones' loaded through ajax. Using it for one of the projects that I am working with. Don't think its great, but works for me. http://oltsm.blogspot.com/2007/06/ra-captcha-idea-for-ajax-b...
abhijit·19년 전·discusscheck out this one at swivel.http://www.swivel.com/graphs/show/8977818very interesting. :-)