how is a raven like a writing desk? from Alice in Wonderland

The answer according to the author, Lewis Carroll, which was printed in the 1896 edition of the book: "Enquiries have been so often addressed to me, as to whether any answer to the Hatter’s Riddle can be imagined, that I may as well put on record here what seems to me to be a fairly appropriate answer,: "Because it can produce a few notes, though they are very flat; and it is nevar put with the wrong end in front!". This, however, is merely an afterthought; the Riddle as originally invented, had no answer at all".