Challenging Sudoku Twelve Logic Puzzles (Vol 1)
Chapter 19: Two Challenging (DiffLev 18-20) Columnarized Puzzles (numbers 117-118)
- Step-by-step instructions for solving Puzzle 117, (83/144) Diff: 18/93.2432.3412.2346.9992
- Step-by-step instructions for solving Puzzle 118, (88/144) Diff: 20/9887.5243.2362.A135.5455