Lobe

Long ago, Lobe had lived inside a music box, spinning below a comb of thin metal teeth. Its edge had been dotted with tiny bumps, and each bump, as Lobe turned, plucked one tooth — plink — before letting it go. The bumps were arranged just so, and because Lobe spun at a steady pace, the plinks fell into a tune. Lobe never chose the notes; the shape of its bumps did. But it was Lobe's faithful turning that carried the melody around and around, the same little song every time the box was wound. That was the day young Lobe understood what it was for: a spinning thing can only spin — it can't tap or beat or count time by itself — but add a bump in the right place, and dumb, plain rotation becomes a rhythm. The information lived in the profile of the cam; the spin only played it back. When the music box's lid finally cracked, the workshop lifted Lobe out, dusted its edge, and set a new follower-rod on top so it could keep making beats out of turning.

The first day at the workshop, Cog rolled over to watch the grey wheel turn and the little rod tick above it. "Show me what you do." Lobe turned once, slow and deliberate. The bump swung up; the rod climbed; the bump slid past; the rod dropped — tap. "That. You gave me a steady spin. I gave you back a beat. I don't add any motion of my own — I convert the rotation you already have into a rise and a fall, over and over. Change the shape of my bump and I change the rhythm: a tall bump for a big lift, two bumps for a double-tap. The when is baked into my edge." Cog rolled around the wheel once, watching the rod keep perfect time. "You make motion dance," it said, and settled back to give Lobe room to spin.

An apprentice named Pip hooked Lobe up to a hand-crank and balanced a tiny hammer on top as the follower. "Crank me slow." Pip turned the handle; Lobe spun; the bump came around and lifted the hammer, then let it fall — tap. Around again — tap. Again — tap. A perfect, even beat filled the corner. "You hear that? Your steady cranking turned into a drumbeat. You didn't tap the hammer once — I did, every single time my bump came around." Pip cranked faster, and the taps came quicker, still perfectly spaced. "Speed the spin, speed the beat — but the pattern stays mine. Now watch." Lobe held still while Pip swapped in a wheel with two bumps; when he cranked again, the hammer went tap-tap … tap-tap … tap-tap, a double-knock instead of a single. "Two bumps, double the taps. A music box plucks its notes this way. An engine opens its valves at exactly the right moment this way — that's valve timing, a camshaft telling each valve precisely when. A toy makes a figure wave and bow this way. All of us take a plain spin and give it timing." Pip cranked and cranked, grinning at the neat pattern coming out of nothing but a turn.