Dorothy marveled at the Scarecrow's collection. "Scarecrow, you sure have been reading a lot lately!"

"Absolutely! See, after I failed 18.01 I decided to switch from mechanical engineering to literature."

"You failed 18.01? Is that Pythagorean theorem still giving you trouble?"

"Don't remind me. Course 21 is much easier, you see: writers use a lot of words but end up not saying very much."

"Oh, you mean the way you do?"

The Scarecrow glared at Dorothy in disapproval.

---- -- - ---- -- - ---- -- - ----. (1913)
A  A


-- --- --- ---- -- -----, -- --- --- ----- -- -----, ... (1859) 
       AA                        BB


--- ----- -- -- ------ - -----, --- ----- -- -- ------ - -----. (1923)
              B              A             A


--- ---- -- ---- ---- ---, --- ---- -- ---- ----, --- ---- -- ----- ---- --- ... (1954)
 A                      B


------ -- -----, ----- ------, ... (1820) 
   BB  B  A


---- - ------, ---- - ------, ---- - ------ ------, ... (1854) 
A                                           BB