Indiana Code Title 4. State Offices and Administration § 4-32.3-2-3

(1) Each participant receives at least one (1) card, board, pad, or piece of paper marked off into twenty-five (25) squares that are arranged in five (5) vertical rows of five (5) squares each, with each row designated by a single letter, and each box containing a number, from one (1) to seventy-five (75), except the center box, which is always marked with the word "free".

(2) As the caller of the game announces a letter and number combination, each player covers the square corresponding to the announced number, letter, or combination of numbers and letters.

(3) The winner of each game is the player who is the first to properly cover a predetermined and announced pattern of squares upon the card used by the player.