Which Pokémon game was the first to introduce gym puzzles?

Question

by puzzles I mean stuff like the ice puzzle for 8th gym in ORAS

Answer 1

Pokemon Gym puzzles originate from the first generation or games; Pokemon Red, Blue, Yellow and Green. The first gym to introduce this concept was the Vermilion gym's garbage can switch puzzle.

Source: Experience

Answer 2

I suppose it depends on how you define "puzzle". Red/Blue/Yellow had several gyms with what I would call puzzles. Vermillion City's switch-in-the-garbage-can being the first. Saffron had the warp panel maze, while Fuchia had the invisible wall maze. And finally, Viridian had the spin panel maze.