Carbo

Carbo had learned what her four hands were for back in her village, when she was small.

Her family were weavers — the otters who made the nets and ropes and pipes that tied the whole village together. And the first time little Carbo had tried to help, she'd panicked. Every knot needed to hold four strands at once, and she kept dropping strands, sure she was doing it wrong, sure her four hands were somehow too many.

Her grandmother had sat beside her and taken one of her small hands in each of her own. "You feel scattered, don't you? Like all four hands are pulling different ways?"

Carbo had nodded, close to tears.

"That's not scattered, little one. That's reach." Her grandmother spread Carbo's four arms out gently, one at a time, until they pointed away from each other like the spokes of a wheel. "One hand can hold one thing. But four hands — four hands can hold a whole net. A rope. A junction where the water splits four ways. You're not too many. You're made for the joining nobody else can do."

Carbo looked at her four open hands. The scattered feeling didn't vanish, but it changed shape. It stopped feeling like too much and started feeling like enough for four. Somehow that made it possible to try again.

By the time she was six she could tie a knot that held four strands without looking. And she understood, in the quiet way you understand things in your hands before your head catches up, that being able to hold four things at once made almost anything possible — long chains, branching nets, rings that closed on themselves. Whole shapes.

She walked to the ChemQuest academy when she was twenty-two, because a place that studied how things fit together ought to want the atom that fits with almost everything.

Beaker met her at the gate. He didn't ask her to prove she was clever. He asked one question. "What is carbon?"

Carbo didn't answer in words. She reached out with her four hands and, one by one, caught the four things nearest her — a stray hydrogen, a bit of oxygen, another wandering carbon, and Beaker's own outstretched paw — and held them all at once, steady, in a wide four-cornered spread.

Then she let three go and kept only Beaker's paw, and looked up at him.

"I have four hands," she said, "because I have four electrons to share. When I take your hand, I put one of my electrons in it and you put one of yours in mine, and the shared pair holds us together. I can do that four times over. That's why I can build long chains, and rings, and nets. The hands aren't a trick. They're just the electrons, out where you can see them."

Beaker looked at the shape she'd made and unmade in the space of a breath. "You belong here," he said.

Carbo's workshop was always crowded, because things came to her to be joined.

One afternoon a boy came in dragging his feet. He'd been given two pieces that wouldn't fit — a hydrogen and an oxygen — and no matter how he pushed them, they wouldn't hold. "They just won't stick," he said. "I've been at it all morning. I think I'm doing it wrong."

Carbo knew that slump. She'd felt it over the knots.

"You're not doing it wrong," she said. "You're just missing the middle. Hydrogen and oxygen don't want to grab each other hard on their own. They need a joining-piece." She held out one hand. "Give them here."

The boy passed her the hydrogen. She took it in one hand. He passed her the oxygen. She took it in a second. Then she reached her other two hands out to two more hydrogens waiting nearby, and all at once the whole cluster clicked into a neat little shape and sat still, holding itself.

The boy stared. "It's — solid. It just worked."

"Because I'm in the middle now," Carbo said. "One carbon, four hands, holding four partners. That's methane — the stuff that burns to cook your dinner." She turned the shape gently in her hands. "Chain me to another carbon and you get the fuel in a lamp. String a hundred of us together with hydrogen along the sides and you've got a fat, or an oil, or a wax. Loop us into a six-sided ring and you've got the sugar your body runs on. Add nitrogen and you can build the proteins in your own arm."

She let the shape rest in the boy's palms. "Almost everything in your body that isn't water is built on my chains. Not because I'm magic. Because I've got four hands, and I keep them open."