Scrabble of points for each lettered tile is based on the letter's frequency in standard English; commonly used letters such as vowels are worth one point, while less common letters score higher, with Q and Z each worth 10 points. The game also has two blank tiles that are unmarked and carry no point value. The blank tiles can be used as substitutes for any letter; once laid on the board, however, the choice is fixed. Other language sets use different letter set distributions with different point values. Tiles are usually made of wood or plastic and are square and thick,
Tile drainage his native Scotland to his farm in Seneca County, New York. Johnston labored to lay worth of clay tile on . The effort paid off by increasing his wheat yield from 12 bushels per acre to 60 bu/acre. Johnston, "...father of tile drainage in America...", continued to advocate tile drainage throughout his life, attributing his success as a farmer to the formula "D,C, and D" (dung, credit, and drainage). The expansion of drainage networks was an important technical aspect of Westward Expansion in the 19th century. Although land in the United States was parceled out in accordance with the Public