Masks are a recurring motif in The Yellow Mythos, with references to the Pallid Mask and The King In Yellow being asked to unmask at the masquerade ball in the Play.
A mask appears in The Mask At The Window.
Mr Wake is described as having a face like a wax mask while Mr Wilde wears wax ears that do match his yellow face.
Masks is the title of one of the poems in the Yellow Dresses sequence as well as an unrelated poem.
See also Commedia dell'arte