Sentence:  The design consists of repeated squares, each bisected by diagonals that form triangles filled with <WSD>vermiculation</WSD> (Pl[ate] 11, reveal pattern d). Design 2, in windows [18 and 30], has a ground similar to Design 1, but the stripes are overlaid with a continuous scroll pattern filled with <WSD>vermiculation</WSD> in umber line (Pl. 11, reveal pattern f). 
Meaning of the word marked with <WSD> tags:  A pattern of irregular wavy lines resembling worms or their casts or tracks, found on the plumage of birds, used to decorate artworks and buildings, etc. (from early 17th c.)