<?php
// Initialize plugin.
plugin_add_hook('CAPTCHA', 'plugin_riddlecaptcha');

// Implement a simple riddle CAPTCHA.
function plugin_riddlecaptcha() {
	$riddles = array(
		array('Are you a spammer? (yes or no)', 'NO'),
		array('Are you human? (yes or no)', 'YES'),
		array('Do you hate spam? (yes or no)', 'YES'),
		array('Do you solve captchas for money? (yes or no)', 'NO'),
		array('Fire is... (hot or cold)', 'HOT'),
		array('Are you posing anonymously? (yes or no)', 'YES'),
		array('Ice is... (hot or cold)', 'COLD'),
		array('Enter the value of ten plus six', '16'), 
                array('Is this a mathcaptcha? (yes or no)', 'NO'),
		array('Enter the value of 5 plus seven', '12'),
		array('Please type the second word in this sentence.', 'TYPE'),
		array('What word is fourth in this sentence?', 'FOURTH')
	);

	return $riddles[ array_rand($riddles) ];
}