The questions keep branching out. What is the drawing meant to show? Empty spaces on the shelves? So then the geezer is being sarcastic about “I wouldn’t have any of that stuff in my library”? Or they really are audiobooks, on physical CDs with shiny plastic cases? And then Zack is dumbfounded because he has never heard of audiobooks? Or instead, Zack is dumbfounded because he is quite familiar with audiobooks, but always in electronic or virtual form and never before this in a physical recording?