This labyrinth – with a silhouette of the fictional detective Sherlock Holmes at its center – is used as a calibration target for the cameras and laser that are part of SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals), one of the instruments aboard NASA’s Perseverance Mars rover. The image was captured by the Autofocus and Context Imager on SHERLOC on May 11, 2024, the 1,147th day, or sol, of the mission, as the rover team sought to confirm it had successfully addressed an issue with a stuck lens cover.