1976
National Gallery of Art, 1893
National Gallery of Art, 1939
National Gallery of Art, 1936
National Gallery of Art, 1475
National Gallery of Art, 1904
National Gallery of Art, 1864
National Gallery of Art, 1940
National Gallery of Art, 1935
Zeisler, Richard S., 1976
National Gallery of Art, 1470
National Gallery of Art, 1887
![Flagstones (a) [trial proof 2]](https://api.nga.gov/iiif/76074520-bf5e-4032-bec1-580b18de84a4/full/843,/0/default.jpg)
![0 through 9 [working proof]](https://api.nga.gov/iiif/8e7dce8d-eb00-4aa9-b0d5-4ccf95263a08/full/843,/0/default.jpg)
