Ivory nodded. "Then I'll get you proof."
She went home that night and built it.
In the basement of her mother's rented apartment in Englewood, Ivory had a workshop. Not the kind you see in magazines: a folding table, a secondhand 3D printer that jammed every 20 minutes, bins of salvaged parts from junkyards across the South Side, and a single work lamp clamped to a shelf.
Over the next 4 days, sleeping 3 hours a night, she built a 1:5 scale replica of the SD9 harmonic drive. She printed the gears from ABS plastic with the same tooth profile as the originals. She rigged a small motor to simulate the operating frequency. Then she ran it at 62 hertz, the original spec. The gears turned smooth: no fractures, no hesitation.
She changed the frequency to 68 hertz. Within 40 minutes, the teeth began to crack. Same pattern, same location, every time. She recorded the whole thing on her phone: 5 minutes of footage that showed the problem, the cause, and the fix, all on a folding table in a basement in Englewood.
She sent the video to Nathan. He watched it three times. Then he did something he had never done in 9 years at Stonebridge: he went over Brent Calloway's head. He forwarded the video directly to Arthur Pemberton, chairman of the board, with a single line:
"Sir, you need to see this. We have 72 hours."
72 hours. That was the window. 3 days before the default clause kicked in and the Department of Defense could legally terminate the contract. 3 days before Stonebridge lost $300 million and probably its future.
Garrett didn't know about the video. Brent didn't know about the video. The only people who had seen it were Nathan, Pemberton, and the woman who made it in her basement with a $50 3D printer.
The clock was ticking, and the only person who could stop it had just been thrown off the factory floor. What happens when a billion-dollar company's last hope walks in wearing steel-toed boots she bought at a thrift store?
Ivory Young didn't learn machines in a classroom. She learned them the way most people learn to breathe: because there was no other choice. She grew up in Englewood. If you know Chicago, you know what that means; if you don't, it means the kind of neighborhood where ambulance sirens are background noise and grocery stores have bulletproof glass at the register.