# Is the "rocket" pattern inversible?

The rocket pattern in slitherlink is when a 3 sees a 1 in a diagonal, with two crosses (the exhaust) on the opposite side.

    3
x 1
x


two lines can be added adjacent to the 3 and opposite to the 1, making the top of the rocket.

    _
3|
x 1
x


I used the reverse pattern several times, but I cannot prove that it is true or just a coincidence.

    _                     _
3|                    3|
1           ====>   x 1
x



Is there a proof that the "reverse rocket" is a valid pattern?

• What a coincidence, I just got back to slitherlink again yesterday after years of not playing it. Thanks for your question! Apr 20, 2022 at 8:05
• @justhalf it is hard to find a good slitherlink pattern guide. Apr 21, 2022 at 2:34