A Riddle
You are presented with 12 coins and a balance. Of the 12 coins, 11 have the same mass. The 12th coin is an off coin, slightly heavier or slightly lighter, however, it is never greater than 2 equal coins. (2 coins will always tip the balance). You are allowed only 3 uses of the balance to determine which coin is the off coin, and if it is off-heavier or off-lighter. Is this possible? Prove your answer.