Jigsaw Sudoku in Large Font — Squiggly Regions, Comfortable Font, Different Challenge! Jigsaw Sudoku (also called Squiggly Sudoku, Irregular Sudoku, or Nonomino Sudoku) plays by the same rules as classic Sudoku — except the nine regions are no longer neat 3x3 boxes. They twist and sprawl into irregular, jigsaw-like shapes. This changes everything. The irregular regions force you to use the "Law of Leftovers" technique, plus all standard Sudoku logic. The results are puzzles that feel genuinely different from classic Sudoku. What's Inside 100 Jigsaw Sudoku puzzles - Easy to medium difficulty levels - Large font — comfortable to read and solve - 7 x 7.5 inch compact format - Solving instructions and all solutions Squiggly Regions. Large Font. Different Rules. More Fun. By DJAPE — PhD in Computer Science, Washington Post puzzle contributor since 2006, author of the world's most popular Jigsaw Sudoku series. A great gift for Sudoku fans who want something fresh!