TOAST is zero, so not TO from TOLLS, leaving 1 in LLS
HOLES and POLES both 1, retained when changed first letter, so one in OLES, but TOAST removes second O, so 1 in LES
so we have:
1 in **LLS
1 in **LES
if it was third spot L, okay. fifth spot S, okay. But they can't both be that fourth letter.
Meaning we know there's 1 in: **L*S
testing with POLAR.
POLAR is equivalent to a shift from POLES to POLER, because the A is in TOAST and is 0.
so if POLAR is 1, changing last S to R did nothing, and the third letter is L
if POLAR is 0, changing last S to R dropped the point, hence last letter is S
~~ POLAR got 1
so third letter is L
**L**