Mutatis mutandi

Back in the good ol' days when the good sisters did the brothers' laundry, one of the brothers put his athletic supporter in with his dirty laundry. The newly-arrived German schwester had never seen such a thing before, and assumed that the poor brother had worn his knickers to shreds. When his clean laundry came back, he found that his athletic supporter had been neatly mended with some spare cloth that the sister had at hand...

from a pretty, lacey liturgical vestment that had been discarded.