Liberty Cuffs

Sewn in using a hidden stitch, enlisted men in the U.S. Navy wore them hidden on the inside of the cuffs of their uniform while on duty. While on shore leave, sailors would turn their cuffs up exposing an intricate array of embroidered patches.This a phenomenon that started in the late 1800's and continued until sometime during the 1970's.

Steve McQueen sported them in the 1966 movie "The Sand Pebbles":

Here's a fantastic collection belonging to Dan Smith: