Knight's Quest 
"Actually," the troll says.  "It could be a man after all.  A man crawls on all fours in the morning -- metaphorically speaking, that is, where 'morning' is meant as the early part of a man's life, when he is but an infant and he crawls on his hands and knees.  Then afternoon would be taken as the middle of his life, when a man walks on two legs.  Evening would be when the man is old and requires a cane, and again, we must resort to metaphors to understand that the cane is to be regarded as a third leg -- you are getting this, aren't you?" 

"I understood you up until the word 'metaphorically,'" you reply. 

"But," you add, "wouldn't it make better sense for it to be a pony?" 

"But," you add, "if you say it's a man, then it's a man."