Though many variations have been introduced as bingo has grown into a multimillion-dollar segment of the gambling industry, the basic premise of the game remains the same: to match randomly drawn numbers to corresponding numbers on a bingo card in a specific pattern, traditionally a straight line across, up and down, or diagonally. Most bingo halls rotate a broad range of patterns during any given bingo session. Those patterns can be as simple as a “corners” game, where you have to match the numbers in the four corners of your card to win, or as creative as a “butterfly” game, where winning numbers create that pattern on the bingo card.

Numbers are marked with flat-ended ink bottles called “daubers” that work much like highlighters — bright enough to make matched numbers easily identifiable, but light enough so as not to obscure the numbers printed on the card. Recently, bingo halls also have begun offering electronic daubers, especially to assist the visually impaired.