Last time: "This weak example of mine, it just proves my theory about Moriarty…"

I raised an eyebrow at that and continued rubbing the cream on the now shrinking welts "Oh? And what's that theory?" I could never have prepared myself for what his answer was

"Moriarty is my soul mate."

I jumped slightly in surprise (probably accidently jabbing his face too in the process… he'd deserve it, bloody git…) I spluttered "Wh-what! How do you figure that one?"

That insufferable git just gave an "Oh-You-Idiot" chuckle and responded "You made the mistake most people would about soul mates. No, there is no attraction, romantically, sexually or otherwise between Moriarty and myself…"

"Hold on! But you said-"

"We are soul mates. Yes."

I finished with his face and washed my hands clean of the healing cream and sat down with my black coffee beside my friend again. I was admittedly curious of his words, "I have a feeling I will regret asking, but how are you and Moriarty 'Soul mates' without attraction?"

Sherlock leaned forward in his seat; chin perched on thin steepled hands. "Imagine yourself on an average line graph with an x/y axis."

I didn't understand where he was going with this at all, or even the connection between math and soul mates, but I did as I was told.

He said "Have you thought of it?"

"Yes."

"Where have you placed yourself on the graph?"

"Just at a random point, why?

Sherlock took a piece of paper with his lab notes and turned it over to its back and sketched a simple graph. He past it to me and said "Write it down here."

I did so, placing myself at the 5,5 coordinate and passed it back to the detective. He took one look and nodded "Very good, now, ignoring the interesting psychology behind your so called 'random' choice of numbers, tell me where your soul mate would fall on your graph?"

"Wouldn't my soul mate be on the same point as me?"

"Ah that is the interesting thing isn't it? Because you couldn't be more wrong."

I bristled in annoyance "Well, there is no need to be rude about it! Tell me then, where would you find your soul mate on the graph?"

Sherlock took up the pencil again and sketched an abstract continuation of the graph by adding a z axis and placed a small dot at -5,-5,-5, or, dead opposite of my own point "That is your soul mate."

I looked at the page then back up to my friend "Explain."

"A soul mate, by definition, must be your opposite. It is that certain person that completes you to put it romantically, but mathematically, your soul mate is your perfect inverse."

"Alright, explain why Moriarty 'completes' you then?"

Sherlock leaned back in his seat and twirled the pencil between his long fingers.

"It is interesting. One of the original theories behind soul mates was that each of the two soul mates were just two halves of the same whole, whether that 'whole' was a complete soul , 'truth', 'perfection' or what have you is up for debate."

"I am very busy, Sherlock, if you could cut the lecture and just explain-"

"I am explaining. Think about it, is there anyone else who has challenged me as Moriarty has?"

"I suppose not…"

"And Moriarty is a criminal consultant, and a genius at that, while I am a genius consulting detective."

"What does that have to do with the graph? You and Moriarty are complete opposites…"

"No. If Moriarty and I were opposites then he would be stupid, because I am intelligent and the opposite of intelligent is stupid."

"When you put it like that then it makes it seem so simple… but I thought you said Moriarty and you were-"

"We are perfect inverse" he tapped the graph with the tip of the pencil "We are both equally intelligent and equally talented, but we are at odds with one another. We challenge each other and push each other further."

"I suppose there are many parallels between the two of you. Moriarty is almost a perfect representation of you if you had decided to become a criminal instead of a detective."

Sherlock chuckled "Now you're beginning to understand. But my theory gets a bit more complicated from there…"

I took a gulp from my coffee and made a non-commental noise. My friend continued speaking

"On the topic of love, it is easier to fall in love with a partial soul mate then it is to love a complete or 'perfect' soul mate. Opposites attract and such" He paused and watched me drink for a moment before making a thoughtful noise "Now that I think about it, that makes you my partial soul mate, doesn't it?"

Needless to say, coffee was sprayed all over the table in front of me upon hearing this statement.