play is determined this way: Each new word formed in a play is scored separately, and then those scores are added up. The value of each tile is indicated on the tile, and blank tiles are worth zero points. The main word (defined as the word containing every played letter) is scored. The letter values of the tiles are added up, and tiles placed on Double Letter Score (DLS) and Triple Letter Score (TLS) squares are doubled or tripled in value, respectively. Tiles placed on Double Word Score (DWS) or Triple Word Score (TWS) squares double or triple the value of the word(s) that include those tiles, respectively. In particular, the center square (H8) is considered a DWS, and the first play is doubled in value. If any "hook" words are played (e.g. playing ANEROID while "hooking" the A to BETTING to make ABETTING), the scores for each word are added separately. This is common for "parallel" plays that make up to eight words in one turn. Premium squares apply only when newly placed tiles cover them. Any subsequent plays do not count those premium squares. If a player covers both letter and word premium squares with a single word, the letter premium(s) is/are calculated first, followed by the word premium(s). If a player makes a play where the main word covers two DWS squares, the value of that word is doubled, then redoubled (i.e. 4× the word value). Similarly, if the main word covers two TWS squares, the value of that word is tripled, then re-tripled (9× the word value). Such plays are often referred to as "double-doubles" and "triple-triples" respectively. It is theoretically possible to achieve a play covering three TWS squares (a 27× word score), although this is extremely improbable without constructive setup and collaboration. Plays covering a DWS and a TWS simultaneously (6× the word value, or 18× if a DWS and two TWS squares are covered) are only possible if a player misses the center star on the first turn, and the play goes unchallenged (this is valid under North American tournament rules). Finally, if seven tiles have been laid on the board in one turn, known as a "bingo" in North America and as a "bonus" elsewhere, after all of the words formed have been scored, 50 bonus points are added. When the letters to be drawn have run out, the final play can