1972–1974
Robert Knisel, 1974
Gemini G.E.L., 1974
Gemini G.E.L., 1969
Gemini G.E.L., 1972
Gemini G.E.L., 1971
Gemini G.E.L., 1980
Ronald Davis, 1980
Gemini G.E.L., 1994
Jeff Wasserman, 1972
![Figure 0 [trial proof]](https://api.nga.gov/iiif/63fe52a2-5065-4d46-b6db-11e71dcc1ab3/full/843,/0/default.jpg)
![Drypoint Theta [special proof]](https://api.nga.gov/iiif/86d9b732-bd19-4790-b277-3298550bbd77/full/843,/0/default.jpg)
![Untitled [working proof]](https://api.nga.gov/iiif/e74ddd17-dc42-4043-b220-7e1ef87f77d9/full/843,/0/default.jpg)
![Figure 7 [trial proof]](https://api.nga.gov/iiif/158ec2d0-a368-490e-8fc9-6aa84d55cb13/full/843,/0/default.jpg)