This happened to my sweater on Friday.
I found seven (seven! really seven!) vintage shell buttons that are all the same size (!) in my button box. They are sisters, not twins, but all have four holes, and most of them have a little lip around the edge.
These mystical seven buttons were all floating loose in a particularly sentimental button box. The stash came from a Goodwill excursion on the Oregon Coast, in the middle of a girl's getaway weekend. It was packaged in a huge canning jar with "Fido" stamped on the lid. Faithful indeed.
These buttons have been poured out onto baking sheets and sorted through with friends, some destined to become eyes for sock monkeys and monsters, others filling in for lost buttons on work shirts - but these special seven were waiting for this little sweater.