 In the 1970s he began to remove elements from spaces, for example sandblasting away layers of paint (at Galleria Toselli, Milan, in 1973) or removing the partition walls separating an exhibition space from the gallery office.More dramatically, in his piece "Installation" (1970) at Pomona College, he created a work by reconfiguring the interior space of a gallery and then leaving the gallery open, without a door, 24 hours a day, introducing light and the noise of the street into the gallery as experiential elements.For another early work at the Claire Copley Gallery in Los Angeles, in 1974, he removed a crucial wall that protected the office space from view, framing the art gallery's behind-the-scenes business operations as something worth viewing itself.