Given the single digit pattern:

- Code: Select all
`d d d | . c . | . . .`

. . 5 | . 5 . | . . .

d d d | . c . | . . .

-----------------------

. . . | . c . | . . .

. . . | . c . | . . .

. . . | . c . | . . .

-----------------------

a a 5 | . 5 . | . . .

. . b | . c . | . . .

. . b | . c . | . . .

When there is a 5 in one or more of each of the a, b, c, and d cells, then there is both a finned X-Wing in r27c35 and an Empty Rectangle in square/block 7 combined with a strong link in r2c35.

The finned X-Wing would eliminate 5 from the b cells and destroy the Empty Rectangle, while the Empty Rectangle would eliminate the 5 in r7c5 and destroy the finned X-Wing. When done at the same time though, it should logically be possible to eliminate the digit 5 from both r7c5 and the b cells.

(I have no idea how often this pattern would occur, but it has made me think twice about whether I want to implement Finned X-Wings)

EDIT - The c and d cells are just there to avoid other types of eliminations, what I was interested in was the Finned X-Wing in r27c35 combined with the Empty Rectangle in square/block 7.