A safety match can’t light on just anything. Half of what it needs lives on the box: the red phosphorus is in the striking strip, and the head carries the other half, so a match loose in a pocket stays a stick of wood until the two halves are brought together on purpose. The invention wasn’t a better flame. It was splitting the fire in two and giving each half to a different object. Most of the things I trust work that way: a lock and its key, a question and someone willing to answer it.