Why is a Raven is like a writing desk?

Carroll's answer to why a raven is like a writing desk? "Because it can produce a few notes, tho they are very flat; and it is never put with the wrong end in front!" I'm sure your thighs are now sore from the repeated slapping they took after you read that line.

I love Alice in wounder land and Alice through the looking glass by Lewis Carol.  This is a book from my childhood and one that I still have a copy of today. 

The British Library London
Alice