Disclaimer: I don't own Marvel stuff.

Warnings: Surprisingly, not many here. ScienceBoyfriends. Cute things.

Author's Note: With how heavy some of my other writing is, like in my novel and my current massive Avengers fanfic enterprise, it's nice to get a break. Thank you to the person who requested this fic on my tumblr.

The Physics of Emotions

Tony did a little spin, grinning as holographic representations of every piece to his Mark VII suit designs came to three-dimensional life around him. He turned his head, glancing at Doctor Banner from the corner of his eyes.

The man looked absolutely rapt, hands falling from the tablet he'd been fiddling with as he took in the next of Tony's toys in his workshop.

"It gets better." Tony let out a little laugh, scooping his hand down into one of the arm gauntlets. It covered his arm, orange and blue and yellow light, each representing a different part of the design. All of the wires were visible, as were the metal support struts, which clung to his bare arm. With his free hand, he pulled holographic plates over, placing them where they would fit on his arm, building the suit from light.

"Wow." Bruce pushed his glasses up higher on the bridge of his nose. He crossed his arm over his chest, that protective, closed off way he always did when thinking. Tony waited patiently. He'd discovered patience worked best when Banner was concerned.

They'd been doing this for a month now. Making science. Tony had been grinning like an idiot for about a month now too, so much so his mouth hurt in the morning. There was finally someone around who spoke the same language as him. Someone who had a mind as sharp and as fast as him.

Tony never wanted this to end.

Doctor Banner joined in after a little while, fitting together the holographic pieces of suit around Tony, who tried standing still—he'd never been good at that—for the whole process. It was like solving a puzzle. Tony already knew how all the pieces fit, but he wouldn't spoil the fun, so he didn't say anything as Bruce played around with the assembly.

Tony yawned, not bothering to stifle it. He was still trying to stand still. Bruce had been making little yawns for a while now, all behind a covered hand like Tony wouldn't notice. Tony glanced at the clock. It was already well after midnight.

He shook out his limbs, the hologram following his movements in a ridiculous way. He laughed, smile bright and shining with the frame of his suit's helmet around it in a bright yellow. Bruce grabbed the faceplate of the helmet, pressing it into place. Tony laughed into the hand, then brushed it away when Bruce didn't move it right away.

"Let me show you something." Tony stepped off the projector, suit falling away from him, leaving him in his usual black pants and Black Sabbath shirt, arc reactor glowing softly beneath it. He waved for Bruce to follow him, and the doctor did, albeit slowly. He was yawning again.

Tony sat down on the work bench, Bruce following in suit. He reached under the table, pulling out a little box. It was glass with a metal base. The original glass had been replaced, because he'd broken it—necessity, really—and the core had been put back in, afterwards, though it barely even produced any light anymore.

He smiled faintly, putting the little box on the table. Proof that Tony Stark has a heart. A lot of people would have scoffed at that. And then half of NYC blew up and not all of it, because he'd had the heart to take what should have been a one way trip into space with a nuke in his arms. People really didn't joke about it anymore.

"This was…" Tony frowned. Bruce was leaning on the table, arms crossed beneath his head. His breaths were soft, even, eyes closed. Damn. Tony rubbed the heel of his palm against his eyes, trying to push the sleep out of them, but it lingered.

Leaning down, Tony mimicked Bruce's position, only he kept one hand on the box as he closed his eyes.