The deck consists of 81 cards varying in four features: number (one, two, or three); symbol (diamond, squiggle, or oval); shading (solid, striped, or open); and color (red, green, or blue). Each possible combination of features (e.g., a card with three striped green ovals) appears precisely once in the deck.
If you click on 3 cards, which are Set, they will disappear and be replaced by another ones. The faster you find it the more points you get. The object of the game is to get as many points as possible. "Find Set" will show you a Set, but it will cost you 500 points. And if you select 3 cards and it is not a Set - you've got 100 points penalty. Game ends when all cards from deck are gone and there are no Sets on the table.