In my previous post I used the line “Can you dig it? I knew that you could.” It’s a line I've been using for fifty years, since I heard Billy Crystal deploy it in a routine on Saturday Night Live in which he portrayed an old jazzman called Face.
Crystal’s routine was based on people he knew from his childhood, jazz musicians who came into the Commodore Music Shop on 42nd Street in Manhattan:

That’s Billy Crystal’s father Jack in the plaid shirt on the right. Larger image here.