But I noticed that in the latest difficulty rating that I know, Finned X-Wings are rated as 3.4, while Skyscrapers are rated as 6.6. This allows us to make a puzzle harder by adding the number at * that converts the Finned X-Wing into a Skyscraper.

- Code: Select all
`x=original X-Wing, f=original fin, *=extra number`

. x . | . x . | . . .

------+-------+------

f * . | . x . | . . .

Here is an example, with Finned X-Wing on 1 in columns 37:

(There is a Skyscraper on 4 in rows 27 that does not work much.)

- Code: Select all
`. . . | . . . | 8 . 3`

3 . . | 5 7 . | . . 2

. . 6 | . . 9 | 7 . .

------+-------+------

. . . | 4 . . | 5 . 9

. . 5 | . 8 . | 4 . .

1 4 . | . . . | . . 8

------+-------+------

. 9 7 | . . 1 | . . 5

. . . | . . . | . . .

5 . 2 | . . 4 | 3 . .

With extra 4@r2c3, the Finned X-Wing becomes a Skyscraper,thus difficulty raises from 3.4 to 6.6:

- Code: Select all
`. . . | . . . | 8 . 3`

3 . 4 | 5 7 . | . . 2

. . 6 | . . 9 | 7 . .

------+-------+------

. . . | 4 . . | 5 . 9

. . 5 | . 8 . | 4 . .

1 4 . | . . . | . . 8

------+-------+------

. 9 7 | . . 1 | . . 5

. . . | . . . | . . .

5 . 2 | . . 4 | 3 . .

I don't think such things should be allowed, so I suggest increasing the rating of Finned X-Wing or decrease that of Skyscraper(I prefer the latter).