Look at history of razors + microscope shots of man's chin before and after shaving.
Extreme CU bristles on man's chin. MS man sitting in front of microscope on a tripod, scientist Edgar Herman looks through microscope lens. Edgar passes the man a series of antique razors to try out, they are from Roman era, Medieval China and Shakespearean German cut-throat razors. Various shots modern disposable razors and electric razors. Man tries out electric razor. Extreme CU (through microscope) of man's chin showing smooth bit where he has shaved.
Note: picture slips at some points on version transferred on PM3398.