Iven began his teaching hour with two pieces of metal that looked the same.
He put them on the clinic’s worktable and asked the assistants which one belonged in the charging collar. No one answered immediately, which pleased him more than a lucky guess would have. Tallo sat beside the window with his healing hand supported, attending as an observer rather than a demonstration nobody had asked his body to give.
One assistant turned a piece toward the lamp. Another checked the marked angle with Emren’s gauge. The third found the heat discoloration on the altered seat and asked whether polishing it away would restore the working face.
“No,” Iven said. “It might remove evidence of where the load went. Measure the shape first.”
They measured.
The difference was small enough that a hurried worker could persuade a familiar clamp to close over either piece. Under load, only one would share contact across the face it was meant to use. The other concentrated demand into a bright narrow line. A wrong fit did not need to look dramatic to become an injury.
Iven showed the path through a disconnected practice housing. He used no living graft as the test load. The clinic’s dummy block held a thermometer and a simple indicator whose face anyone in the room could read. When the altered seat received the measured supply, the high contact warmed first. He stopped before it became hot enough to damage the block and let each assistant compare the faces.
