[Updated with photo from match and Wikipedia entry. Thanks to Janus Lodahl and Bernie DeKoven].
Somehow I missed this, but Danish situationist Asger Jorn designed a three-sided football (that is, soccer) game back in 1961.
And the Asger Jorn museum in Silkeborg inaugurated their Triolectic football court last weekend. This is from the opening match. (Image courtesy of Midtjyllands Avis.)
It’s a returning question: what does it mean to declare that a game is an artwork of sorts?
And even more media: A somewhat unedited 2012 document of Triolectic Soccer: