Pseudonym Pairs is a coordination game for global proof-of-unique-human, through monthly pseudonym events that last 15 minutes, where every single person on Earth is randomly paired together with another person, 1-on-1, to verify that the other is a human being, in a pseudo-anonymous context. The proof-of-unique-human is that you are with the same person for the whole event. The proof-of-unique-human is untraceable from month to month, much like cash. True anonymity.
The Pseudonym Pairs system is built around the functions register(), immigrate(), dispute() and reassign(). The schedule is enforced with scheduler(). Personhood is verified with the public mapping proofOfPersonhood. Mixing is done with external contracts. Incredibly simple.