Five Differences Between Sherlock and Mycroft, and One Way In Which They Are Just the Same

One, Sherlock plays the violin. And horrible, high screeches notwithstanding, he does so quite beautifully.

Mycroft is tone-deaf, couldn't dance a waltz if someone tapped the 1-2-3 on the floor with his umbrella for him.

"I don't see the point in what is basically Mathematics," said Mycroft, a condescending smile on his lips.

Sherlock rolled his eyes and put back the violin on his shoulders, this time picking up the bow and setting it on the strings to produce a sound. Mycroft already looked on the verge of developing a migraine. He thought he'd help it along when he had won his argument. "That's so typical of you. You don't see a practical use for it in your world domination game and dismiss it as useless." John had a strong, sudden urge to intervene and tell Sherlock that this was like the pot calling the kettle black, but if Sherlock noticed his expression, it didn't make any difference to him because he continued. "It's not just Maths," he insisted, "it's no wonder you can't get a right note." And to demonstrate it he started playing an air on the violin.

Mycroft simply stared at him with mildly concealed bitterness. He was thinking of what to do with that would utterly annoy Sherlock. He could take the violin, but there was a more effective way. A slow smile crossed his face but avoided his lips.

Two, Sherlock likes to run, hunt down, chase people, tackle them and fight. The dirtier the better.

Mycroft does the same from his desk. A quick call to the right person and he achieves the same result. Without even getting dust on his expensive three piece suit.

"Come on, John!" Almost yells Sherlock, launching himself at a run after a fleeing suspect. Really, Sherlock didn't look at all like a cop, why did everyone just assume the worst and start running?

John followed, but after a few alleys and a quick detour through some private house's garden, Sherlock closed in on the suspect, almost close enough to grasp. He sprung forward and grabbed the man's knees; they both ended up on the floor, quite roughed up.

Sherlock didn't let go as he got his breath back, but before he was ready to stand a black car with tinted windows stopped in front of the entrance of the alley they were in. John was catching up, but as he saw the car he slowed down to a jog.

"NO!" exclaimed Sherlock a fraction of an instant before the door slid open and they caught a glimpse of Anthea gesturing at some men who grabbed their unsuspecting suspect by the jacket and hauled him on the seat.

Sherlock was on his feet and the car left quickly before he could reach the handle.

"No, no, no!" He stomped his feet, hands clenching into fists and unclenching. He started pacing the alley, it was not good. Then a most expected bip.

Sorry, I'll let you have the next one.

Mycroft

Cavities? Or are you having your stomach stapled? SH

Three, Sherlock doesn't eat when he's on a case, digestion slows him down, and to be honest, he couldn't remember.

Having important government duties doesn't help Mycroft's diet.

When they are on a case, John's belly would start to growl angrily whenever he starts following Sherlock's lifestyle for longer than 12hours. The consultant detective may forget to eat for days, and when he doesn't forget he refuses to, claiming it would slow his brain's speed down (even then he would be in the top league, but John has learned early which arguments he has no chance of winning) but John Watson's stomach is always careful to remind him every time he skips a meal or two (it has made a compromise in the name of their friendship). If Sherlock notices he will stop to let him eat something (which is the compromise Sherlock has made for their friendship).

John could not help but get worried about, as did Mrs. Hudson, who became much more motherly towards Sherlock every time they closed a case, cooking fantastic meals.

After the last case was closed, they returned to 221b, and Sherlock's stomach finally got green light to growl. Mrs Hudson had Lestrade put her on his speed dial, so when the boys opened the front door, she welcomed them with a tray full of freshly baked scones for their tea. "I'm afraid I cooked a little too much for lunch today, I have a lot of leftovers of roast and potatoes. Would you like some for dinner?" John's mouth watered a bit at the assault of delicious smells. The only thing they had ingested that day were two cups of the Yard's coffee. Two cups too many, in his opinion. They thanked their landlady and Sherlock took the scones, waiting for John to open their door and make him tea. John felt spoiled and a bit taken advantage of, but Sherlock ate, and he was relieved.

Mycroft had to tell his assistant the day he started his diet. He had to confess to Anthea every last hiding place for candy, chocolate, marshmallows and even water crackers. He ate absentmindedly when he was rigging elections in some strategically important nation, or organising a rebellion in South America, or checking the security reports on his brother. And that was terrible on his diet.

The woman did a twice weekly sweep of his office and limo, and also arranged it so that his groceries would arrive home free of saturated fats and cholesterol.

She was so good at this job that after a few weeks Mycroft was truly miserable.

Time to make a visit to his brother, he decided.

Four, Sherlock deals with boredom the same way he would a rabid dog: with a loaded gun and sharp aim.

Mycroft has a hobby, and he likes to practice it at Sherlock's place. The bugs there were all his, and Anthea's.

John could not explain this even to himself. What was the deal with the Holmeses brothers and their inevitable attraction to deadly weapons when there wasn't anything else to do? Couldn't they learn to crochet or get involved in any outdoor activity that didn't transform the path to his bedroom into a battlefield?

It was like playing a warped version of clue. Someday Lestrade would come over and found him dead and guess: Sherlock, in the living room, with his bloody gun.

For now it was still the smiley face on Mrs. Hudson's wallpaper.

One afternoon John was going to gracefully retreat to his room in order to avoid being a casualty. He crossed path with Mycroft, who was walking out of the kitchen brandishing a big, sharp knife. Assuming he was about to commit a Sherlocide, John stopped in his tracks and raised his arms. "Whoa. I haven't seen anything," he said, unsure if it was better to divert his eyes or keep his gaze on the blade.

Mycroft walked past and cleared his throat at his brother. "Can you stop that? I'm trying to prepare dinner."

Sherlock aimed the gun at his brother. "Pity I'm out of shots," he grunted between clenched teeth.

John breathed out of relief.

But in the end, when John gets home at night, tired from his shift at the surgery, he slips naked into his bed, and when they blindfold him he doesn't know whose hand is touching his thigh, or whose mouth is on his, he doesn't know which of the two Holmeses is fucking him and whose talented mouth sucking his cock.

Until he closes his hand around Sherlock's long, tousled curls, and then he knows.