3D model created from a 2D public domain image. The imagery is superimposed on both sides to emphasis the fragments colour. Dimensions are relatively accurate except for the depth of the scan which I have estimated to be 38mm, this is the same for similar items.
[Fresco fragment with siren](https://www.metmuseum.org/art/collection/search/253327?searchField=All&sortBy=Relevance&ao=on&showOnly=openAccess&ft=roman+wall+fragment&offset=0&rpp=80&pos=34) via The Metropolitan Museum of Art is licensed under CC0 1.0