Use two lights to see the reactions of the shadows
Over the shoulder and 45 to the camera's right- This second camera adds a little more light to the right side of the face and almost brings out the shadow more on the right side.
45 degrees to right of camera and 180 to the left- This almost takes all of the shadow off of the left side because we are adding a light on the main dark spot.
45 degrees to the left of the camera and 180 to the right- Like the last one this takes away a lot if the shadow from the dark side of the face
180 degrees to the right and 45 to the right- This adds extra light to the right side and brings out darker shadows on the left side creating kind of a half and half picture
180 degrees to the left and 45 to the left- Like the last one there is more light on the left side and brings out darker shadows on the right side.
Both lights facing the back- This makes the subject darker, but other than last time we moved the subject closer to the light so it is not completely dark and this gives the shoulders more light and adds some light to the lower face.