A crossword is a word puzzle that usually takes the form of a square or
a rectangular grid of white- and black-shaded squares. The goal is to
fill the white squares with letters, forming words or phrases, by
solving clues, which lead to the answers. In languages that are written
left-to-right, the answer words and phrases are placed in the grid from
left to right ("across") and from top to bottom ("down"). The shaded
squares are used to separate the words or phrases.
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