From LC himself' "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, viz: 'Because it can produce a few notes, tho they are very flat; and it is never put with the wrong end in front!' This, however, is merely an afterthought; the Riddle, as originally invented, had no answer at all."
Well, similes like this are crafted with reason due to the acuity of the person who came up with it. Such a thing could actually be immensely elaborate and reasonable. Perhaps the two things are relative for the concepts in mind. Maybe it seems to him that both are things from which deep contemplation arise. Look back on the story which the simile originated. Try to link the purpose of it to the personal thought processes of he who wrote it.