How Everything Works on Instagram: "What looks like a fully built, lived-in movie set is actually just an actor walking through empty space. A few lights, a green wall, and careful blocking are all it takes. Everything else — the walls, depth, movement, atmosphere — is added later. Green screen works by isolating a single color so it can be digitally replaced, but the real magic is how convincing it becomes once lighting, shadows, and camera motion are matched. The actor isn’t reacting to a real