Minoru Hirata, A Happening on the Street, 1970 (Collective Kumo at the Tenji Intersection of Fukuoka, February 26, 1970), photo: courtesy of Taka Ishii Gallery, Tokyo. © Minoru Hirata

Oscar Dumas, Two photographs taken behind the photographer’s back, #1, 2010, Beijing. © Oscar Dumas

Penelope Umbrico, 8,799,661 Suns, 2011, images taken from Flickr (detail), 3 August, 2011. © Penelope Umbrico