Octave and Rill

Rill went first, because a chord has to start moving before it can go anywhere.

"Play your rock," she told the boy. He struck the chord — solid, all at once, thud. "Now don't hit them together. Roll them. Bottom, middle, top, one after another." He did, and the chord rippled out, sparkling, water over stones.

"There's your first change," Rill said, doing a happy otter-roll. "Un-stacked. Instead of a wall of sound all at once, it's a stream — one note at a time, flowing. That's an arpeggio, remember. Same three notes; I just spread them out over time." She rolled it again, quick and light. "Hear how it moved? It's not a rock anymore. It's walking." She tilted her head. "But it's walking on level ground. It ripples along, but it doesn't rise. For the rising —" she looked over at Octave — "you need floors."

Octave took over, because rising means having somewhere higher to go.

"A chord doesn't have to stay on one floor," Octave rumbled. He took the boy's three notes and played them low — deep, in the basement. Then he played the same three notes an octave higher — bright, up in the attic. "Same chord. Same notes. Just a whole floor up. Low-and-rumbly, or high-and-sparkly, and it's still your chord either way." He played basement, then attic, and the room felt like an elevator going up. "That's what I spread — not time, height. I take a chord and give it more than one floor to live on."

The boy played his chord low, then high. "It's the same chord up there," he said. "Just... higher. Sparklier."

"Sparklier," Octave agreed, pleased. "The attic's always got more sparkle. But watch what happens when Rill and I put our two spreads together."

And then they combined, and the rock became a rising river of light.

Rill started rolling the chord — bottom, middle, top — and instead of stopping at the top, Octave nudged the next note up into the next floor, so Rill kept walking, note by note, right up the staircase of octaves. Bottom, middle, top — then the same notes again, a floor higher — bottom, middle, top — a floor higher still, climbing and rippling all at once, until the chord that had been a rock was a shimmering line sparkling all the way up to the ceiling.

"THAT," said Rill, delighted, "is a chord that climbs."

"Two spreads at once," rumbled Octave. "Rill spreads it across time — one note after another, so it flows. I spread it across floors — up through the octaves, so it rises. And separately —"

"— I can make it flow, but only on one level," said Rill.

"— and I can make it rise, but only in one thud per floor," said Octave. "But together — flowing and climbing, one note at a time, up floor after floor — we take your heavy rock of a chord and turn it into a river running uphill. Same three notes the whole way. Just spread across time and height at once."

The boy tried it — rolling the chord and letting it climb, floor by floor, note by note — and his heavy chord lifted off the ground and sparkled all the way up, exactly like the floating, rising song he'd been hearing in his head.