Книга "Extremely Challenging Sudoku | 200+ Sudoku Hard Puzzles".Sudoku puzzles will basically order your brain to think logically about how and what numbers to place in which boxes. You aren't getting any clues when playing the game. Instead, your brain will look for patterns to use as clues. You can't even search the answers on Google. The 200+ puzzles in this book are extremely challenging so you best be ready. Это и многое другое вы найдете в книге Extremely Challenging Sudoku . 200+ Sudoku Hard Puzzles (Puzzle Therapist)