1st. Two or more cards played at once.
2d. Any card dropped with its face upward, or in any
way exposed on or above the table, even though
snatched up so quickly that no one can name it.
3d. Every card so held by a player that his partner can
see any portion of its face.
71. A card dropped on the floor or elsewhere below the table is not
an exposed card.
72. If two or more cards be played at once, by either of the dealer’s
adversaries, the dealer shall have the right to call which one he
pleases to the current trick, and the other card or cards shall
remain face upward on the table and may be called at any time.
73. If, without waiting for his partner to play, either of the
dealer’s adversaries should play on the table the best card or lead
one which is a winning card, as against the dealer and dummy, or
should continue (without waiting for his partner to play) to lead
several such cards, the dealer may demand that the partner of the
player in fault, win, if he can, the first, or any other of these
tricks, and the other cards thus improperly played are exposed cards.
74. If either or both of the dealer’s adversaries throw his or their
cards on the table face upward, such cards are exposed and are liable
to be called; but if either adversary retain his hand he cannot be
forced to abandon it. If, however, the dealer should say, “I have
the rest,” or any other words indicating that the remaining tricks
are his, the adversaries of the dealer are not liable to have any of
their cards called should they expose them, believing the dealer’s
claim to be true, should it subsequently prove false.
75. If a player who has rendered himself liable to have the highest
or lowest of a suit called (Laws 82, 91, 92 and 100), fail to play
as directed, or if, when called on to lead one suit, lead another,
having in his hand one or more cards of the suit demanded (Law 76),
or if called upon to win or lose a trick, fail to do so when he can
(Laws 73, 82 and 100), he is liable to the penalty for revoke, unless
such play be corrected before the trick is turned and quitted.