But the rebus remains the core of the story, bootstrapping societies from complete ignorance of the very idea of writing to lives that cannot be imagined without it.
The doorsteps were worn into curves, and the ancient tiles which lined the porch were marked with the rebus of a cheese and a man after the original builder.
But at some point—the Sumerians of the third millennium bc are usually awarded first prize, though Ms Ferrara makes a case for Egypt—people stumbled on the " rebus principle" .