This is a simple example of an implementation of the Elo rating system popularized by the game of Chess. Essentially, matches are chosen by selecting "decent" matchups (nearby players rating-wise) sequentially, such that every single player gets a match each turn. The players then play the matches and update their ratings, where the power of a player represents how strong they are. Ideally, the players will eventually sort themselves in decreasing order of power.

Note: since we make sure every player has matchup and the order matchups are created is random, the players may have to play with far away opponents to get a match.