Vito Acconci, Seedbed, 1972 - exhibited at the Sonnabend gallery, New York
a constructed ramp - approximately 22 x 16 feet - rose up 2 feet from the gallery floor to a side wall. Acconci occupied the space under the ramp three days every week for a period of 8 hours, masturbating and speaking amorously to visitors through a microphone connected to speakers in the gallery space.