Glasses

Yes indeed, I say to myself, pen in hand, I can keep hold of the thread and let it lead me back to the first impression. The little story is all there, I can touch it from point to point; for the thread, as I call it, is a row of coloured beads on a string. None of the beads are missing - at least I think they're not: that's exactly what I shall amuse myself with finding out.