What he is saying is that captchas work solely on the fact that computers aren't fantastic at character recognition yet, so there isn't much way to have bots fo

What he is saying is that captchas work solely on the fact that computers aren't fantastic at character recognition yet, so there isn't much way to have bots force their way in. This method will work temporarily, because it's new, and obscure. But if someone specifically targeted a website that used this, they would just have to figure out how many puzzles there are, and design a more simple application to solve it each one, rather than create a groundbreaking solution to better OCR (optical character recognition). This system only works if there are unlimited, non repeating puzzles.