Rentoy is a 16th-century Spanish and Mexican card game for two players or teams that involved signalling.
Rentoy is first mentioned by Cervantes (1547–1616) in The Illustrious Kitchen Maid along with a game called Presa y Pinta (possibly Lansquenet) and appears to have been a popular 16th and 17th century Spanish card game.
[1] It was still popular enough in the early 19th century to appear in an autobiography by Periquillo Sarniento in 1816.
[2] It was the most popular game among Mexican soldiers in pulquieras (bars) and barracks.
It required "careful and discrete communication by gesture or mutter between the partners, which all expected but ran contrary to the rules."