In 1627 a group of sailors wanted to communicate a grievance to the captain of one of the King’s ships. Technically this amounted to mutiny, which was punishable by death, so they needed a way to express their solidarity without revealing any one of them as the leader and inviting retribution against him.
The answer was to arrange their 76 signatures in a circle, demanding that their allowances be distributed and the ship be victualed before they would weigh anchor. (I don’t know whether the captain agreed.)
From the U.K. National Archives.