She finished the sixth movement at 4:15. Holzer examined it under the loupe and set it down.
The other five sat in a row on the grey felt. Same caliber, same supplier, same hands doing the assembly. She couldn't tell them apart without checking the serial numbers. Holzer could. He'd separated them into two groups of three without explaining the criteria.
She'd watched him do this for eleven years. Once she asked.
"They're all correct," he said.
She tried everything. She timed the rate against a reference. She measured amplitude with a timing machine. She photographed the escapements at identical magnification and overlaid them. The groups were identical by every instrument she owned.
The seventh movement would go to a customer. The first six would go to the drawer, in their two groups of three.
She finished the sixth movement at 4:15. Holzer picked it up. Counted. Set it down with the group on the left.
After he went home she moved it to the right group to see if he'd notice. He did, the next morning, before he'd taken off his coat.
She still didn't know what the groups meant. She was starting to suspect Holzer didn't either — that the sorting was real and the explanation wasn't, that his hands knew something his loupe was only pretending to verify.