The first pic a regular 1956. The rest the oddity. On the loop of the 6 it appears the d mm was repunched. The six loop comes all the way to the spine of the six, abnormal. Also it look like the metal is raised up a second time inside the loop of the six. The first picture is a regular 1956.
Your coin has been hit and damaged. Ever seen a cashier open a roll of coins on the edge of a cash drawer? They sometime crack it open like an egg and it causes damage to the coins.
and the above is one of a BaZillion ways a coin can get damaged. look up Coin Rolling Machine damage and you'll also see how it can deform, distort, etc the letters and numbers around a coin similar to yours. And with the money recirculation that occurs most coins will get damaged by that ONE process, which is one of a bazillion ways a coin can get damaged. And there is nothing that prevents a coin from getting damaged multiple times by multiple ways.
...the hit on the 6...the topmost metal of the right loop was shifted over to the left, creating what looks like a hole of a “d”...usually a hit just creates a contact mark or flattens the numeral or letter...we all agree to PMD...copper is a soft material and is easily moved this way....Spark
