He never exceeded those invisible boundaries. Until Elena left.

He wrote a letter to Elena: "I have been living by iso 2768. But you taught me the most important tolerance — accepting what doesn't fit the drawing. Come back. I'll leave room for the irregular."

One midnight, he opened the old workshop. Among calipers and micrometers, he found a brass gear he’d made as an apprentice. It didn't fit any shaft. Its teeth were irregular. Scrap , his master had said.

I notice you've asked me to generate a story based on the phrase — which in Italian means "ISO 2768 tolerance."

ISO 2768 is a technical standard for general tolerances in mechanical engineering (for linear and angular dimensions without individual tolerance indications).