In 1964, Danish artist Asger Jorn published "The Application of the Triolectical Method in General Situology," a philosophical tract that rebuked dualistic society. Nobody knew what the hell he was talking about, so he invented three-sided football to illustrate.
The game, as this interesting clip shows, is still very much alive today, even though it is almost entirely unknown compared to bourgeois two-team football.
By promoting tertiary systems over binary ones, Jorn sought to replace confrontation with collaboration. But hearing three-sided football players talking about the game, it pretty much sounds like soccer with a side of betrayal. [NotCot]