one or more tiles for an equal number from the bag, scoring nothing, an option available only if at least seven tiles remain in the bag. Play at least one tile on the board, adding the value of all words formed to the player's cumulative score. A proper play uses one or more of the player's tiles to form a continuous string of letters that make a word (the play's "main word") on the board, reading either left-to-right or top-to-bottom. The main word must either use the letters of one or more previously played words or else have at least one of its tiles horizontally or vertically adjacent to an already played word. If any words other than the main word are formed by the play, they are scored as well and are subject to the same criteria of acceptability. See Scoring for more details. A blank tile may represent any letter and scores zero points, regardless of its placement or what letter it represents. Its placement on a double-word or triple-word square causes the corresponding premium to be applied to the word(s) in which it is used. Once a blank tile is placed, it remains that particular letter for the remainder of the game. After making a play, the player announces the score for that play, and then, if the game is being played with a clock, starts the opponent's clock. The player can change their play as long as the player's clock is running, but commits to the play when they start the opponent's clock. The player then draws tiles from the bag to replenish their rack to seven tiles. If there are not enough tiles in the bag to do so, the player takes all the remaining tiles. If a player has made a play and has not yet drawn a tile, the opponent may choose to challenge any or all words formed by the play. The player challenged must then look up the words in question using a specified word source (such as the NASPA Word List, the Official Scrabble Players Dictionary, or Collins Scrabble Words), and if one or more of them is found to be unacceptable, the play is removed from the board, the player returns the newly played tiles to their rack, and the turn is forfeited. In tournament play, a challenge may be to the entire play or any one or more