Though the design by Strauss and Davis for “Improvement in Fastening Pocket-Openings” that was patented in 1873 included a version of this pocket, the small pocket as we know it today was not an element of the blue jeans mass-produced by Levi Strauss & Co. until the 1890s, when the target buyers for the work trousers were carpenters, railroad workers, farmers, and miners—hence the gold nuggets. Today the small pocket remains a feature of all kinds of different jeans, a vestige of a time when jeans were strictly casual pants. These tiny pockets were superfluous on suit pants because suit jackets had inside pockets for watches.

And what about those rivets at each corner of the watch pocket (and all the other pockets)? They’re designed to reinforce stress points so as to prevent ripping—the real breakthrough of U.S. Patent No. 139,121 secured by Strauss and Davis a century and a half ago.