The carefully crafted (non-random) sequence above tries to fake out the script and succeeds every time. It reveals the script's own predictability, and why you shouldn't rely on it too much as a yardstick for testing your brain's psuedo-randomness.

You can generate a sequence like this if you can see what the program thinks your next input will be, and choosing different.

It's fairly easy to debug/modify the javascript to do this