In the mid-1980s as a further education lecturer I was mocked by some more traditional colleagues for using “lantern slides”, their term for the then newfangled technology of the overhead projector, or OHP. These Luddites strutted the corridors with coffee-tinted sheaves of notes stuffed untidily under their arms. They would sweep into the classroom, fling their pencil-written papyri on the lectern and, without so much as a glance at their students, commence reading out loud.