Good. So why require the user to add up the values? Some alternatives: * Click all the dice with value 5. * Click all the pictures with a roll of 4 and 5. (ea

Good. So why require the user to add up the values? Some alternatives: * Click all the dice with value 5. * Click all the pictures with a roll of 4 and 5. (each picture shows a pair of dice). If you test for pattern recognizing the number of dots on the top of the dice, then you can just verify only that. No need to make a human user to do a task that a computer can easily do. I can imagine a bunch of users pulling out their phone calculator app to do the addition, which should tell how stupid this captcha is.