One CAPTCHA that seems pretty common at the moment is pointing an animal in the direction of a finger, either N, NE, E, SE, etc... by clicking a button to change the animals current direction.
It just occurred to me that there is a 1/8 chance of being assigned the correct position to begin with. I created a new account on Twitter to check and, after three tries, got one pointing in the right direction.
Why are these CAPTCHA's a thing? 12.5% of bots will pass this by clicking the submit button straight away. Am I missing something?