Ah, I see. I'd forgotten that instance. How it seems to work is that those inside corner tiles get done by the second of the two adjacent tiles. So all you need to do is also smooth the other tile next to those spots and they get smoothed too. I think it is kinda like the adjacent tiles do half of the inside ones so both need to be done.
Even though in the picture, there are really 3 adjacent tiles, you'll need to smooth all REACHABLE and adjacent tiles to get the corners done. I think.
Even though in the picture, there are really 3 adjacent tiles, you'll need to smooth all REACHABLE and adjacent tiles to get the corners done. I think.