be-dyrnan

be-dyrnan, wk.v: to hide, conceal. (beh-DUER-nahn / bɛ-ˈdyr-nan)

An initial M in a medieval manuscript has a letter A entwined inside it, with birds and fantastical creatures hiding within.
Lindisfarne Gospels; England (monastery of Lindisfarne), c. 700-3rd quarter of 10th century; British Library, Cotton MS Nero D IV, f. 18v. [iiif.bl.uk]