Rule-driven, like his indexical artworks (image: 640 numbers between 1 and 10, 1969) John Cage’s Museumcircle opens at ZOLLAMT MMK in Frankfurt. Conceived by Cage 1985-91 to apply his aleatoric composition strategies to curation, the scheme calls on local museums to loan a venue works, from which a random selection are “hung or placed in chance-determined positions.” Its first staging in several years, Museumcircle last showed at Toronto’s Justina M. Barnicke Gallery in 2015.