Hollow spheres (detail). ca. 1650. Photograph taken at an Exhibit in the Bode-Museum, Berlin. Cc0 Licence 1.0. In the public domain in the United States because the artist died over 70 years ago. via https://commons.wikimedia.org/wiki/File:Ivory_works_-_hollow_spheres_by_Lorenz_Zick,_c._1650,_covered_cups_by_unknown_German_artist(s),_c._1620,_ivory_-_Bode-Museum_-_DSC03386.JPG
Standing cup. 17th c. Possibly by the workshop of Lorenz Zick. Collection of the Metropolitan Museum of Art, New York. In the public domain. via https://www.metmuseum.org/art/collection/search/191622
Contrefaitkugel. 17th c. Collection of the Kunsthistorisches Museum, Vienna. Image © Europeana Collections. In the public domain in the United States because the artist died over 70 years ago. via https://www.europeana.eu/portal/en/record/15502/KK_4503.html