Lays out a crossword from words with clues. Returns two matrices of the same size: puzzle (the game position: "-" is a blank cell, a word's number is on its first cell, "0" marks the other cells where a letter goes, and "a/d" such as "3/4" appears when an across word and a down word start in the same cell) and solution (the same matrix with the correct letters, one grapheme per cell). placements lists every word with its number, clue, direction (across/down) and start cell; unplaced lists words that did not fit. Offer more words than you need: the engine keeps the best layout it finds. Native letters (Ñ, Ç, ẞ…) stay one cell each. Free, no usage limit. The same seed gives the same crossword.