
All players form a single team. In the first round (level 1) each player receives 1 card, in the second round (level 2) they receive 2 cards, and so on.
At each level the team members must put down all their cards in increasing order in the center of the table on an open stack, one after the other. For example (4 players, level 1): 18-34-41-73. The players do not take turns in any particular order.
Whoever wants to put down a card, simply does so. Watch out, here's where it gets interesting: the players must not disclose anything about their own cards - no sharing of information, no secret signals. So how does it actually work? …