Naum Gabo (1890- 1977) was influential as an artist in the Constructivist movement. Gabo used the placement of planes to imply volume to the viewer. Gabo's sculptures were more concerned with space than mass which is apparent in his piece Two Cubes. This piece presents with "visual clarity the inner core and the path of its own construction" in the Stereometric Method. His intent was "conceptual penetration of form". Gabo also created kinetic mobile sculptures to produce virtual volume.