“Right,” said George, “let’s try again, shall we. I’ll start: Oxford Circus.”
“Erm... Trafalgar Square,” replied an enthusiastic Baldrick.
“Good one. I’ll go Regent’s Park.”
“Oh. Er... Camden Market!”
“Damn it, Balders. How many more times do I have to explain? No transverse laterals are allowed during a waxing moon unless Cripplefield’s variations have been invoked.”
“Oh. Sorry. How ’bout Elephant & Castle then?”
“No, everyone knows you can’t go south of the river this time of night. Do we really have to go through the entire set of rules again?”
“What are they doing?” a befuddled Buffy asked Blackadder, the two of them having observed the exchange from the doorway.
“Well, George, the slightly more intelligent one, in relative terms, is trying to teach Baldrick, who is as close to absolute zero as it is possible for a human brain to achieve in the field of intelligence, to play Mornington Crescent; an exercise about as futile as attempting to teach a comatose fish to play Grieg’s Piano Concerto while blindfolded.”
http://www.tthfanfic.org/Story-16291-19/