I assumed it was about Wally's favourite colour being green (or perhaps that the fridge brilliance comes with his later actions regarding his love of the colour green), but reading the author's commentary below the strip*
(Wally doesn't have a PokeNav in Ruby or Sapphire, just Emerald)
I wondered if the unsigned fridge brilliance might have been that it was his Emerald PokeNav.
This:
I assumed it was about Wally's favourite colour being green (or perhaps that the fridge brilliance comes with his later actions regarding his love of the colour green), but reading the author's commentary below the strip* I wondered if the unsigned fridge brilliance might have been that it was his Emerald PokeNav.