When I was a child, I answered this question with 'they both begin with "R"' and imagined LC say, "Ah but they don't, you see! A writing desk has a "w" in front of it." I used to be dazzled by the ingenuity of this little escape route to what I thought was the obvious answer. All grown up now (I think), I don't answer it any more like all other questions of life.