The perfect CAPTCHA: Bitpeople

Bitpeople (dot) org was invented by me between 2015 and 2018. It is the perfect CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart). The hardest possible digital Turing test. It is therefore the last to break. It is not unbreakable assuming an infinitely advanced AI (a science fiction scenario that is not real but like any other science fiction could possibly end up being real), nor is any other CAPTCHA, but it is the hardest possible. Anyone interested who was not yet aware of it, feel free to discuss it here. I also solved "reserve payment attack" issue in multihop payments recently (this spring), with a 3-phase commit, also the perfect solution for that problem domain.