got fast fingers?

I found this illustration in a book titled, The New Illustration. It was done by Doug Taylor under art director Peter Nevraumont for client Ruby St.  No information about the illustration's function or purpose was listed, though.  I'm really curious about its application because it's so fun and interactive.  The expression on the man's face is one  part of the illustration that I particularly admire.  I also like the women in the background on either side of the figure, which along with the guns in the foreground, give the overall composition symmetrical balance.