I thought this variant up myself, but after I thought of it, I also saw a reference to it as a modification of Mastermind in a journal paper somewhere. The idea is that after Player 1 submits their guess, Player 2 submits their guess and also has the option of choosing the number of black and white pegs seen by Player 1 for their guess (so the response could be a lie). Each player would only get one lie per game. Also, obviously if the code was guessed correctly, no lie could be used.

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Tristrom Cooke