That would be http://research.microsoft.com/en-us/um/redmond/projects/asirra/ http://research.microsoft.com/en-us/um/redmond/projects/asir... There is also one

That would be http://research.microsoft.com/en-us/um/redmond/projects/asirra/ http://research.microsoft.com/en-us/um/redmond/projects/asir... There is also one where you assemble a puzzle: https://www.keycaptcha.com/ https://www.keycaptcha.com/ They have varying levels of handicapped accessibility though.