Leading lines can be useful in photo composition. Lines in the background and foreground can be used to guide the eye to the subject of the photo. These are leading lines. This can be useful if you have a busy part of the photo or simply want to have some influence over how others view your picture. Think of them as a way of telling the viewer to “hey look at this part of the photo!”
For most of these photos I used natural sunlight and a strobe light with a soft box. I caught the puppy as he was taking a nap or as best as one can take a nap with someone photographing them. When you photograph pets resting just keep your expectations within reason. Do not expect sudden action photos. You generally know you are going to get just resting photos and there are just so many angles you can capture that from.