Description of the game
Each bingo player is given a card marked with a grid containing a unique combination of numbers and, in some countries, blank spaces. The winning pattern to be formed on the card is announced. On each turn, a non-player known as the caller randomly selects a numbered ball from a container and announces the number to all the players. The ball is then set aside so that it cannot be chosen again. Each player searches his card for the called number, and if he finds it, marks it. The element of skill in the game is the ability to search one's card for the called number in the short time before the next number is called.
The caller continues to select and announce numbers until the first player forms the agreed pattern (one line, two lines, full house) on their card and shouts out the name of the pattern or bingo. One of the most common patterns, called full card, blackout and cover-all simply consists of marking all the numbers on the card. Other common patterns are single line, two lines, the four corners, centre cross, L, T, Y, postage stamp (2x2 and in a corner) inner square (4 × 4), roving square (3 × 3), and roving kite (a 3 × 3 diamond). Lines can be made horizontally, vertically, or diagonally. Inner and roving squares and kites must be completely filled; roving squares and kites may be made anywhere on the card.