A Triple Trompe-L'Œil (Midweek Miscellany 4)

Browsing photographs of manuscripts at the Houghton Library, Harvard, I found this unusual example of a trompe-l'œil fly, on a trompe-l'œil face, formed of the edge of a trompe-l'œil piece of parchment:

Department of Printing and Graphic Arts, Houghton Library, 
Harvard University, MS Typ 219, fol. 484r

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