\startquotation Near Göttingen are two hills that are called Die Gleichen --``The Equals''. They were no doubt given this name because, when viewed from a certain angle, they look almost identical. It is reported that David Hilbert used to ask his students why these hills were so called. None of the obvious answers like ``equal height'' or ``equal shape'' satisfied this great scholar, who was a stickler for exactness. Finally he would give the answer himself: ``Because they are equal distances apart from one another.'' \stopquotation