“Ineluctable modality of the visible.” So begin the musings of Stephen Dedalus as he walks along Sandymount Strand in the third chapter of James Joyce’s “Ulys­ses.” “Signatures of all things I am here to read.” The chapter isn’t just a tour de force of prose writing. It’s an exquisitely sensitive depiction of a mind at play. Conscious of his own consciousness, Dedalus monitors his thoughts without reining them in. He’s at once focused and un­focused. Seemingly scattered ideas, sensations and memories coalesce into patterns, into art.