First try running at the wall really fast...
If that doesn't work use an action replay or GameShark. There is NO other way to walk through walls. Any other ways are false and probably involve you ruining your game.
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78DA95DF 44018CB4
that's how
the code is 99FFR342DE
Yes You Can Just use gameshark
It is something on Google which tells you stuff if your stuck on the Pokemon game like were to catch a Pokemon
here is a gameshark 56830098 098
You can get Pollywhirl in Pokemon Leaf Green in Virdian City.
By trading it through Pokemon fire red or Leaf green
No cheating!
past the 8 gyms through victory road
The Pokemon you can get in fire red and not leaf green are Electabuzz and Scyther.
visual boy advance? yes
If I am not mistaken #151 is Mew, which is only obtainable by "migrating" from Pokemon Fire Red or Leaf Green. It's only available in Fire Red or Leaf Green through a special Nintendo Event.
you can't get mamoswine in Pokemon leaf green because it doesn't exist in leaf green