Together Bridge Puzzle Answer 2021: We Were Here

Tiles only stay raised if they are "locked" together by a continuous line on the cave player's mechanism. Puzzle Steps

(from speedrun/walkthrough consensus):

The cave player re-aligns the mechanism starting from the Universe symbol. we were here together bridge puzzle answer

Once the Walker reaches the "Universe" (Black Hole/Dead End) symbol, they must stand there while the Puzzler rebuilds the bridge for the second half. Phase 3 (The Return): Tiles only stay raised if they are "locked"