Phantom Group: Open Conic Plane, 2 Parallel Double
Systems, 2 Parallel Single Systems, 1967
Steel with ground zinc with patina
2 1/4 x 58 1/4 x 56 inches (5.72 x 147.96 x 142.24 cm)

Paper Model for Phantom Group, 1967
pencil, water based paint on cardboard
20 1/2 x 24 1/2 x 1 inches (52.1 x 62.2 x 2.5 cm)

Untitled (Drawing for the Phantom Group), 1967
charcoal and colored pencil on paper
21 3/4 x 14 7/8 inches (55.3 x 37.8 cm)