How to know what sounds are flowing along the wire and into the earpiece of the woman sitting in a corner of the stone courtyard while the city reverberates mid-morning. Steve Reich’s music for marimbas? Standard Chinese Vocabulary for Beginners? Mindfulness exercises for busy executives? The talking book of Jane Eyre? How to guess what she’s looking at so intently, prayerful almost, on her opened screen where it rests on adjoining stone bench. News of the depletion of species? 25 essays to mark by Thursday? Google’s results for Big Bang? The latest downloaded puzzle app? Glinting microchips of November sunlight?