In this example, we will ask three random questions to see whether we are dealing with robot or machine. If you select Quiz Mode, you can have the correct answer returned. This is more for validation of question/answer sets than a quiz, but I'm not stopping you from having fun ;-)
Note - questions are drawn on a random basis so you may be asked the same one more than once.
Want to play with the code? This example front-end is textcaptcha_example.php, and the include file containing the randq function is textcaptcha.php.