Fig. 2

Photos of the simulation classroom and the skull VLR. a The entire classroom, in which a skull is placed on a table in the front of the classroom, the other skull is placed on a table in the middle of the classroom, and pictures of the human skeleton are placed in front of the window. b The skull VLR and projection screen. c The frontal bone separated from the entire skull. d All the bones separated, with the bright white ball representing the center of the original skull