The Fourfold Passage

You enter a circular chamber carved into the mountain's heart, where cold stone surrounds a forest of brass ribs, crystal tubes, and clicking gears. Four sealed gates block the passage ahead, each marked by a different emblem: a gear, a flame, an eye, and an open hand. Blue light crawls through channels around their frames whenever anyone approaches the controls. The air smells of hot metal and snowmelt, while somewhere inside the walls a tiny mechanism counts patiently, waiting for the correct sequence.