Set is a card game designed by Marsha Falco and published by Set Enterprises in 1991. The deck consists of 81 cards varying in four features: number (1, 2, or 3); symbol (diamond, squiggle, or oval); shading (solid, striped, or open); and color (red, green, or purple).

Several games can be played with these cards, all involving the concept of a *set*. A set consists of three cards which satisfy all of these conditions:

- They all have the same number, or they have 3 different numbers
- They all have the same symbol, or they have 3 different symbols
- They all have the same shading, or they have 3 different shadings
- They all have the same color, or they have 3 different colors

- One red striped diamond
- two red solid diamonds
- three red open diamonds