I actually saw a pretty decent captcha the other day on a Chinese website (I think Taobao? I forget.) anyway the cool thing they did was that the text wasn’t in an image it was a looping video, but the text in any one frame was incomplete (only parts of the Chinese characters). And each frame different parts of the characters were visible, with a lot of noise in other parts of the frame where parts of characters would have been in other frames. A human brain sort of smoothed this out between frames and sees the characters clearly, but taking a screenshot was impossible. And becuase I don’t know Chinese I wasn’t able to take a screenshot and ask AI to translate the message. It seemed like a pretty good anti AI method. Of course an algorithm could be made to convert the video into a single frame, but captchas have always been defeatable by a sufficiently motivated attacker, they are only to raise the bar slightly against the swarm of dumb bots.