The small joins inside a zip

A zip stopped halfway gives you two views at once: separate rows above the pull, a joined strip below. I like being able to follow that change without taking the thing apart. The little pull does most of the travelling; the teeth stay where they are.

I prefer the close-up. What looks like a smooth line from farther away turns out to be a lot of small joins, each row holding on to the other. Make it too tidy and the interesting part disappears. It’s slightly ridiculous how much there is to look at in something whose entire job is opening and closing.