i.e. play a spade card. East has a spade card, and thus must follow suit by playing . South, however, does not have any spade card, and thus is allowed to play any card he wants. If he desires to win the trick, he can override North's by playing a diamond card (diamond being the trump), for example . If he does not want to win the trick, he can slough any other suit, such as . Let us assume that he plays , overriding North's card. Now, West still has to follow suit, since he has a spade card, and plays . South's trump card, gives him an opportunity to escape following suit, and he wins the trick. If a player who can follow suit does not do so, or in games with additional restrictions on card play, not following these restrictions is known as a revoke, or 'renege'. A revoke typically cannot be discovered at the time when it is committed, but when a player plays off-suit to a trick, competent opponents will make a mental note that the player does not hold the suit led, and will notice later if the player later plays a card of the suit they were thought to be void in. The situation is similar for other types of revoke. Most game rules prescribe a severe penalty for a revoke and may also result in the hand being voided (a "misdeal"). Decks of cards have been marketed for trick-taking games with the traditional French suit symbols, but in four colors; these are often called "no-revoke" decks, as the color contrast between each suit makes a potential revoking play easier to spot and harder to do accidentally. In some trick games—typically ones in which players are not penalized for winning tricks, and there is no requirement for trumping or following suit when possible—players may slough, or play a card face down. A card so played is incapable of winning the trick; but sloughing has the advantage that the other players cannot see what card is played. As this form of sloughing has the potential to be used to cheat in most games (i.e. playing a winning card face-down to avoid taking an "overtrick" or a trick containing penalty points) and is thus not allowed, sloughing in the vernacular more often refers to simply discarding an off-suit card on a trick, particularly one that