Looks like remnants of a 1, to the left of 1.
A Denver Mint mark to the top right of 1.
An outline in the field of a 1 downward to the back of Denver. 1957D
It looks like the 1 was taken with the Denver and dropped when reinstalling an actual removed 1.
Broken die shown on the left reverse wheat.
We'll see...WHAT? What brought your attention...?