Whenever I play Sudoko, I see the finished puzzle as an overspecified version of the original input. Like 8b/10b, Reed-Solomon codes, turbo codes, or low-density parity-check codes. With ECC the computer has to solve a puzzle to produce the correct data, and with Sudoku the human has to solve a puzzle to produce 81 digits of fun.
Do you think any of these ECC codes would make a good pencil and paper game? (8b/10b -- the home version!)
Is there a good way to represent data as Sudoku puzzles to make the most ridiculous ECC available?