It was long ago during my schooldays, when I first encountered the square-root of minus one. I remember it all very clearly; a bright globe-like class hall, about a hundred round heads of children and Plappa—our mathematician. We nicknamed him Plappa; it was a very much used-up mathematician, loosely screwed together; as the member of the class who was on duty that day would be putting the plug into the socket behind we would hear at first from the megaphone, “Plap-plap-plap-plap—tshshsh.…” Only then the lesson would follow. One day Plappa told us about irrational numbers, and I remember I wept and banged the table with my fist and cried, “I do not want that square-root of minus one; take that square-root of minus one away!” This irrational root grew into me as something strange, forei
