A/N: Written for sleepscribbling for Yuletide 2010. Thanks go to significantowl and basicare for the betas.

Clyde tried drawing them once. Not their physical forms – he has notebooks filled with portraits of Luke and Rani and himself, separately and in various combinations – but them, their lives, their interlinks. It became impossibly complicated, and formed a shape best described as a squogglydon. It isn't complicated, though. He doesn't know what shape it would be if he just drew their relationships to each other, and didn't bother with anyone else; the world expects a triangle.

A triangle has three straight, rigid lines, which touch only briefly, at their very outskirts. The angles in a triangle add up to one hundred and eighty, always. That isn't them; together they are much more than that.

Acute

Luke knew that, as a genetically-engineered, alien-created genius archetype, he was never going to be normal. And that was before you factored in spending the first few years of his life chasing aliens, helping aliens, hiding aliens and having aliens round for tea in his free time.

Clyde claimed full credit for Luke turning out as well as he had.

"I could go into business," he'd said. "Clyde Langer: the world explained. Coolness instilled; success in society guaranteed."

"There aren't that many teenage newborns," Rani had pointed out. "Not much of a market."

"First rule of business, know your market. Easy."

Then the Kejhaff had kidnapped him so that he could instruct them on how best to blend in prior to their invasion. He'd only managed lesson one ("Licking is not an acceptable form of communication.") before they'd rescued him.

"At least you know the idea holds wide appeal," Rani had offered, doing a very bad job of not laughing.

"My intended market is less...gooey," Clyde had said, with as much dignity as possible while dripping with alien saliva.

It was only to be expected that said genetically-engineered, alien-created genius archetype who spent all his time investigating aliens with his mum and his two best friends would manage to fall in love with both his best friends. Apparently that wasn't normal. The world was paired. Two eyes, two arms, two legs. Back in his first year, when he was fourteen-none, he'd read every book about being a teenager that the library had held, and, although he remembered 'What to do when you like your friend like that' and 'So you think you're gay', nowhere did he remember anything about what to do when in love with both your best friends.

And of course he'd only come to that realisation after he moved away and went to university.

Obtuse

Clyde Langer's life had taken quite a surprising turn when he'd met Luke Smith, aliens, and Sarah Jane Smith. He'd never imagined spending his weekend hanging out in an attic, or not being able to tell a careers advisor that he wanted to join a top secret military who dealt with aliens.

On top of everything they dealt with in the course of a perfectly ordinary day, realising he really, really liked both Luke and Rani in a not entirely platonic way shouldn't have been that much of a shock.

He'd always thought Rani was nice looking, since that first day. She'd turned out to be a really, really great mate and it was only now that he was dimly comprehending the terrifying combination. Luke had always been, well, Luke. Lukey Boy. And then he left, and Clyde really, really missed him.

For a minute, when Luke was raving about Sanjay, when he said he was the best mate he'd ever had, Clyde believed him. It was his nightmare. Luke was brave and brilliant and far cleverer than him; he would move on to great things, had already started, and would have other friends, friends almost as clever as him, leaving Clyde Langer behind.

Then everyone laughed, because it was ridiculous, a joke. Luke and Rani and Sarah Jane were his best friends, the best friends he'd ever had, and he was much more than a useless troublemaker taking after his father; they saved the world together.

With Luke away at Oxford University, it was just him and Rani juggling school and aliens and homework. She reminded him about Great Expectations, made the prospect of being one of only two people left on the planet very slightly better than completely horrifying and helped rescue the entire population of the Earth from a warp shunt. Three days later, she was completely unwilling to back him up when he suggested telling Mr Butler, quite truthfully, that an alien ate his homework, but she did help him reconstruct it.

Adjacent

Sanjay and a group from the hall had decided to explore the concept of an all-nighter that didn't involve study, but did involve alcohol, loud music and burgers for breakfast. They'd invited Luke, and he'd decided to try it. They'd arrived early to get in before the bouncers arrived and started asking for the I.D. he didn't have, and had watched as the club filled up, and up. Everyone had a small world about the size of their bodies, draped in a heavy blanket of music, the beat their own, vibrating through their world.

After the dark and the weight of the club, the burger bar was stark, flat, its bright relative emptiness seeming to swallow the queuing teenagers. Their voices sounded small and strained in the resounding silence.

"Do you want to go out sometime? For a drink?" Vicky said.

Luke paused, confused. "We are out."

"No, er, I mean, just us. Going out."

"Oh," Luke said, and tried to remember if Clyde's social lessons had ever covered this. "Well."

There was a pause, their silence underlined by the chatter from the rest of the queue.

Vicky smiled, a wry quirk of her mouth. "Don't worry. Just thought I'd ask."

She sat at a different table when they got their burgers. Sanjay waved Luke to the seat opposite him.

"I was just wondering," Sanjay began, talking between bites of his burger. "Not that you have to tell me or anything, but, if you are, I could warn the girls off in advance."

Luke really wished Clyde was there. "Sorry?"

"Is it just Vicky or all girls?"

He'd thought of Clyde when Vicky asked him. He thought of Rani when Sanjay asked him. Clyde and Rani. Clyde and Rani.

"I don't think I'm gay," he said. "But I'm not interested."

Oblique

Rani Chandra had known, and told various enquiring adults, that she wanted to be a journalist since she was still of the age when they expected to be told 'a princess' or 'a pop star'. She had expected to find herself in odd situations, which she would then report on. She hadn't expected 'odd situations' to involve aliens, nor for this to occur so frequently that it wasn't actually an odd situation.

She still wrote the articles. Destined to never be published - despite and because of the subject matter - they were still good practice.

"That paragraph's very good, Rani," Sarah Jane said, and glanced over at her, looking over the top of her glasses. "But see here," – she pointed at the screen – "if you start this paragraph with a summary, and then elaborate, it's stronger."

"You're our Doctor Watson," Luke said, grinning. "Documenting all our cases."

"What do you think of this?" Clyde passed his sketchbook to Rani; the Mona Lisa glared up at her. "Suit your article?"

"It's great, Clyde."

"Elementary, my dear Watson."

She hadn't expected odd situations to include being quite probably in love with her two best friends. She had no idea how to go about writing this one up.

Supplementary

"Here you go." Sarah Jane handed a mug of tea to Luke and sat down next to him on the sofa. "Hot drink's the best thing on a winter evening. What was it you wanted to talk about?"

"I don't think I'm gay, Mum."

"Okay." She took a sip.

"I mean, I like Clyde. But I like Rani too. None of the books talked about that."

She looked up sharply. "That's not a problem, Luke. Don't think it is. It's not as if everything in the books is normal, and anything not isn't. Really, if they don't mention bisexuality, they're hardly likely to mention that sometimes labels don't fit, and people are just people."

"So I might be gay, and just like Rani?"

"Or you might be Luke." Sarah Jane smiled. "Who likes Clyde and Rani."

Luke nodded.

"A relationship with three people can work just as well as with two people, you know." Sarah stared into the middle distance, her lips curving into a distant smile. "Or as badly, of course."

"What do you think I should do, Mum? I know I'm off at university now, and Clyde and Rani..."

Luke trailed off. Sarah set her mug down and turned to face him.

"I think...I think you and Clyde and Rani have very strong bonds and, right now, you're figuring out how you operate apart. That's very healthy. Distance is the test of a relationship. There's so much new, for all of you, at the moment. Everything needs to settle down, get sorted out, and then you can see how things are."

Complementary

"That one's a Sontaran. If you pinch your eyelid together..."

"Oh yeah, I see. That shadow's the probic vent."

They both stared up in the spring sky. The clouds drifted slowly, the wind barely enough to rustle the new leaves on the trees.

"Clyde?"

"Yeah?"

"I think I like Luke too. In the same way I like you."

"Me too."

Rani propped herself up on her elbow and looked down on Clyde. He looked back up at her.

"Really? Luke?"

"Yeah. See, people think it's like a triangle, all straight lines and points, and really it's like a big wibbly ball of...stuff."

"Stuff?"

"Stuff," Clyde repeated, and gave a decisive nod which worked quite well considering he was lying down.

"Aw, I stuff you too." Rani smiled, and leaned down to kiss him.

"Do you think it'll work?" she continued, lying back down on the grass.

"Course we will. And your dad'll be happy."

"Why's that?"

"He likes Luke. Parents can't help it. So if you go out with me and Luke, he'll be fifty percent happy with your choice of boyfriend, which, my amazing mathematical skills tell me, is a fifty percent rise which should, theoretically, lead to a corresponding drop in the occurrence of 'I don't know what you see in him'."

Rani spoke into an imaginary microphone. "This projected drop is likely to be mirrored by a one hundred percent increase in occurrences of 'He's a nice boy', seeing as Gita Chandra likes Luke just as much as Clyde."

"Leading to a hundred and fifty percent approval swing in the Chandra household!"

Congruent

Clyde and Rani went to Oxford at half-term.

"Sarah Jane said she'd be along in a day or two," Rani told Luke, as they wandered along the High Street. "Depending on how long the investigation takes."

"Let's hope it's not that long," Clyde said. "If our lift home doesn't turn up, we'll be late back. Imagine, the Headmaster's daughter, skipping school!"

Rani raised her hand holding his and dug the elbow of that arm into his side.

"Where're you taking us, then, Lukey Boy? Found any nice restaurants?"

Luke grinned. "If by 'nice', you mean 'sells burgers'."

Rani took Luke's hand. (Two hands, a pair, one each.)

It was all perfectly ordinary. They'd been out together hundreds of times.

In the burger bar, they had a discussion about dating etiquette, going Dutch and who should pay for whom – Clyde paid for Rani, Rani paid for Luke and Luke paid for Clyde – and on the way back, Luke held Clyde's hand.

It was all perfectly ordinary, for their given value of normal.

"I could get to like this normal," Clyde said, and Luke and Rani squeezed his hands.