 His work in the late 1960s and early 1970s consisted of dividing up gallery spaces using partition walls and curtains, and designing environments that reflected or absorbed sound.For his first solo exhibition at the La Jolla Museum of Art, Asher installed a tone generator in one of the gallery walls that effectively cancelled out all sound waves in the room, creating a dead zone in the center of the gallery.In 1969, for the group show “Anti-Illusion