 These are common crossword variants that vary more from a regular crossword than just an unusual grid shape or unusual clues; these crossword variants may be based on different solving principles and require a different solving skill set.Cipher crosswords were invented in Germany in the 19th century.Published under various trade names (including Code Breakers, Code Crackers, and Kaidoku), and not to be confused with cryptic crosswords (ciphertext puzzles are commonly known as cryptograms), a cipher crossword replaces the clues for each entry with clues for each white cell of the grid—an integer from 1 to 26 inclusive is printed in the corner of each.