Reason Lestrade looks confused in season 3 teaser! He goes to take his badge out of his pocket, and it's gone. And he knows right at that moment that Sherlock is back, because he is the only person who could pull this off without him noticing.
▶▶▶ Ring installation // Arnaud Lapierre distorts and reconstructs reality through the layering of reflections and voids. The cylindrical environment warps visitors' perception of space into a simultaneously reconstructed and deconstructed reality.