Captcha forces people to mark mailbox as parking meter
twitter.com
twitter.com
The only pattern it seems to block is repeatedly smashing the skip / ok button.
Now I'm wondering about adversarial responses to captchas that would make unrelated objects indistinguishable to the AI...
As for parking meters, in France, I never saw parking meters like this. We have different kind of ticket distributing machines.
Many websites don't need captcha anyway. They could go with options like OOPSpam API and silently flag spam based on Spam Score.