[detail of worm-holes], Duodecim Prophetae, from a multi-volume Hebrew Bible in quarto published by Robert Estienne (Paris, 1539-44), A1v-2r. (Bodleian Library, Opp. add. 4° I. 246)
Most leaves that are adjacent in the bound book were not so in the gnawed pile. The asymmetry of the holes shown here (greater for earlier signatures in the alphabet) was created as the worm turned.