Y, Z
Y: Yellow
Yellow is a colour that is usually associated with optimism, but that probably wasn't on Sherlock's mind when he graffitied a smiley face on the wall of the flat using a can of yellow spray paint that he picked up on one of his cases. As if that defacement of the wallpaper weren't enough, Sherlock shoots at the yellow smiley face in a fit of boredom. Mrs Hudson is appalled when she notices what he has done to the walls. 'I'm putting this on your rent, young man!' Mrs Hudson threatens Sherlock. He is unfazed by that statement, and surveys his handiwork with pride, just before an explosion knocks him off his feet. (Note to John: Throw out any cans of yellow spray paint that Sherlock has brought home, lest he decides to do more redecorating of the flat in future.)
Z: Zenith
Sherlock is at his zenith when he's with John, and the reverse is true as well. In the words of Lestrade: 'Sherlock Holmes is a great man, and some day, if we're very, very lucky, he may even be a good one.' John helps Sherlock to become a better, nicer person, and Sherlock helps John to get over the scars of war by introducing John to new battles. (Don't ask me what the reasoning behind that is!) They are the making of each other, and they would find it difficult to survive without one another. The two residents of 221B, Baker Street met for a reason. If they hadn't, the world would never have had the privilege of knowing a certain consulting detective and army doctor: Sherlock Holmes and Dr John Watson.
A/N: I'm sorry for my choice of words for Y and Z, but seriously, it's Y and Z! I honestly couldn't think of anything better. Do forgive me. What an awful way to end the fic, but...
Anyway, this is the end of The Baker Street Dictionary! The first multi-chapter fic that I've completed. I did toy with the idea of an index and an appendix for a while, but finally decided against it. The fic is at an end! Thank you very much for reading it, and I greatly appreciate all the follows, favourites, and reviews. Exiguous though they may seem, I do appreciate every one of them.
