1978
National Gallery of Art, 1546
National Gallery of Art, 1840
National Gallery of Art, 1528
National Gallery of Art, 1931
National Gallery of Art, 1870
National Gallery of Art, 1910
National Gallery of Art, 1973
National Gallery of Art, 1667
National Gallery of Art, 1968
National Gallery of Art, 1887
National Gallery of Art, 1970
National Gallery of Art, 1979
![Figure 6 [trial proof]](https://api.nga.gov/iiif/99d11251-16e4-45a2-becd-ca218d8c460b/full/843,/0/default.jpg)
![Light Bulb [trial proof D]](https://api.nga.gov/iiif/35ad584d-a077-40cc-8edb-a5a1d4b70f23/full/843,/0/default.jpg)
![Elements [special proof]](https://api.nga.gov/iiif/cd162326-c0eb-411b-b946-7a574e58572c/full/843,/0/default.jpg)