Collect four cards of the same rank, tip off your partner with a sign only the two of you know, and let them shout “Quatro!” Your opponents, meanwhile, watch for your signs so they can counter you.
Quatro is played by four, six or eight players, in teams of two partners sitting across from each other. There are no turns: everyone puts a card into the center and takes another back, without waiting for anyone, until they hold four cards of the same rank.
Holding four of a kind isn’t enough. Before each round, the two partners agree on a sign that nobody else knows, and it is the partner — never the one holding four of a kind — who shouts “Quatro!” Meanwhile, the other teams watch the signs go by and look for the right moment to shout “Counter!”
A round lasts three minutes at most, and the first team to five points wins the game. The rules cover every case: the delay between two swaps, what happens when nobody wants the center, and the price of one call too many.