Minimalist art would have a profound influence on designers of the 1960s such as Peter Walker, Martha Schwartz, and Hideo Sasaki. On the one hand, Sol LeWitt's space-frame sculptures and Carl Andre's floor sculptures of mass-produced objects allowed a re-thinking of the necessity for walls in the formation of space. Geometry, repetition, and changes in ground plane created a "field of making" in which walls and even plantings were questioned as essential elements of landscape. Equally at issue in applied practice was the perception on the part of Sasaki that landscape had come to be seen as "open space", a white sheet of paper on which to display International Style buildings. This disconnection with the landscape was especially notable in corporate office parks, and Sasaki and Walker addressed this through an attempt to connect interior and exterior spaces.