I spent hours playing mastermind as a kid and this modern day re-incarnation is a really nice twist on the theme. Mastermind was a nice primer for Sudoku, and

I spent hours playing mastermind as a kid and this modern day re-incarnation is a really nice twist on the theme. Mastermind was a nice primer for Sudoku, and probably those that are good at solving Sudoku are good at solving problems involving constraints in general.