Disclaimer:Numb3rs isn't mine; I do not profit from this.

A/N: Happy Mother's Day, mum! (only in the UK, so don't freak out thinking you've forgotten :-) )

A Thousand and One

The sound of paper as it was folded, creased, shuffled was almost soothing. Charlie was getting hypnotized by the repetition of his actions: two valley folds, two mountain folds, make a square base, further fold that into a bird base… steadily, at a rate of one every two to three minutes - the young genius made paper cranes.

He would never have learnt origami if it hadn't been for his mother pulling out the parent card. New Jersey was a lonely place to be for a 13-year-old college student and his mother, both of whom were the span of an entire continent away from home and the rest of their family. An hour every day, simply paper folding, learning new designs, techniques, served two purposes for Margaret Eppes: one, it got her son's mind away from math for a while, at least ostentatiously, and second, it allowed both to spend time together as a family with no distractions, just a little quiet time between mother and son, and if Charlie used that time to open up and talk, maybe about his troubles in school, well that was just fine with her.

In any case, it was only when Charlie's time at Princeton was coming to an end and Margaret had begun packing that she found papers in Charlie's handwriting, all seemingly to do with the mathematics of paper folding. Huzita's axioms, trisecting an arbitrary angle – geniuses will remain geniuses she had thought as she shook her head fondly, placing the papers in a box labelled Princeton Origami, along with some of her and Charlie's more ambitious designs and results from that era.

Fast forward into the new millennium, and Charlie was sitting alone in the solarium, focused on his task. It was late at night; a single lamp was on in the room by whose illumination Charlie continued with the monotony, paper crane after paper crane coming to shape under his hands, heedless of the shadows in the corners, the silence of the house. His parents, as far as he knew, were fast asleep in their bedroom down the hall and blissfully aware that their youngest son had spent a few hours every night, for the past few nights, secluded in the solarium doing nothing other than making paper cranes. Charlie had been careful to clean up after himself. The finished cranes would be put in a box that he would shove under his bed when his eyes would begin to droop with sleep and he would remember he had to be alert for classes in the morning – teaching took just as much, if not more, energy as learning and comprehending and he couldn't afford to be lax.

On the periphery of his mind, Charlie could sense the temptation of giving into the math. The Millennium Problems had always intrigued him, especially P vs NP. During a moment of breathing space at CalSci, Charlie would sometimes indulge himself and spend some time on it, but a part of his brain, and heart, kept him from diving headfirst into it, knowing that it wasn't the solution and if he let himself go, there might be no looking back. His mother was dying, and she needed him.

It was no coincidence, however, that folding a fold model from a crease pattern had been proven to be NP complete.

Distracted as he was making his 275th crane, Charlie did not notice the beam of headlights crossing his face as a car pulled up into the driveway. He did not hear the quiet snick of a key being inserted into a lock, the soft creak of a door being opened, the muted thud of it being shut again. He especially did not hear the thump, thump, thump of feet climbing stairs. It was no surprise therefore, when the hand placed on his shoulder shook him out of his stupor with a sudden jerk and he looked up to see his brother's face half cast in shadow.

"Charlie, what are you doing up so late?" whispered Don.

Charlie said nothing. He simply shrugged, deftly put the final touches on the paper product in his hand and held up the finished crane on the palm of his hand to show to his brother who took it from him and turned it side to side as though examining a strange object.

Charlie took no further notice of his brother and he reached behind his shoulder and pulled another sheet of paper from the stack on the sofa behind him as he sat on the floor, his back leaning against the old piece of furniture. Some of the squares of paper he'd cut from magazines, some pulled from old math books that he didn't much hesitate in tearing apart to feed his endeavour. Some cranes were patterned with drawings reminiscent of an architect's or a city planner's, but that was no matter.

He had just about turned the new sheet of paper into a square base when he heard, rather than saw, his brother sit down cross legged opposite him.

"Paper cranes, huh? Why so many, Chuck?" he heard his brother ask softly.

Using his thumb nail to crease down the fold, Charlie whispered back in kind:

"Senbazuru"

"Excuse me?" Confusion coloured his brother's voice.

"Senbazuru – a thousand origami cranes. According to an ancient Japanese legend, if you fold a thousand paper cranes, a wish of yours will be granted. Long life, recovery from an illness" – Charlie's voice almost broke on the last word – "anything."

"Huh." His elder brother was nothing if not succinct. Charlie paid him no further attention as he steadily moved forward, folding paper crane after paper crane. His brother could have left and he wouldn't have noticed, but he was surprised when his hand came into contact with the warm flesh of another hand as he reached behind him to grab more paper for the third crane since either of them had last spoken.

In silence, Charlie watched as his brother gave him a half-smile as he took a sheet of paper before himself focusing on folding a paper crane himself, getting past the first four folds with relative ease before pausing a moment, as though trying to remember what came next.

A sense of warmth filled Charlie along with a sense of hope as he himself took a piece of paper and raced through the first four folds before slowing down considerably, keeping a careful eye on his brother's progress as Don repeated what Charlie was doing on his own crane-in-the-making.

Together, the two brothers sat silently and folded paper crane after paper crane, crossing the threshold of a thousand cranes at least thrice before Margaret Eppes succumbed to the inevitable and her youngest son to the unsolvable, and even though Don threw out all the paper cranes a few days after his mother's funeral, he kept two which were preserved in a drawer in his apartment for a long time to come.

Khatum (The End)