Vertical Mini Pipes and their Munchers

Nintendo implemented these very strangely.

Vertical mini pipe

0x4h y x a -- a vertical mini pipe with height h. However, this pipe periodically does damage if Mario is standing on it. The object id a means the pipe starts out doing damage, then alternates between no damage -> damage -> no damage.

0x4h y x 9 -- a vertical mini pipe just like above. But it starts the damage/no damage cycle on the no damage leg. So it does the opposite of a, damage-wise: no damage -> damage -> no damage

pipe muncher

0 y x 1 -- a pipe muncher that starts outside of the pipe. It then repeatedly goes in and out of the pipe: out -> in -> out -> ...

0 y x 0 -- a pipe muncher that starts inside the pipe. Just like 1, it repeatedly goes in and out of the pipe except on the opposite cycle: in -> out -> in ...

They must be combined

If you read closely above, the pipe is doing the damage, not the muncher! If you add a pipe muncher to a level by itself, it will repeatedly go up and down, but do no damage at all!

Since the pipe is the one dealing the damage, a vertical mini pipe must be coupled with a pipe muncher. You can add a vertical mini pipe by itself to the level, but the player will be very confused as to why it is damaging them.