Ключевые слова: background, brain, brainstorm, brainteaser, column, composition, difficulty, entertainment, eyeglasses, fill, flat, fun, game, grids, hobby, intelligence, japanese, lay, leisure, logic, math, mathematics, mental, mind, missing, numbers, object, paper, pastime, pencil, place, placement, play, popular, problem, puzzle, rebus, row, sheet, solution, solving, squares, sudoku, table, teaser, top, view, white, wooden, world,