This photos contains the primary element of Aperture called “Focus”.

Aperture is a setting or a tool in a camera where you can navigate the focus of the subject on the camera. This helps the photographer to capture the subject clearly and to control the non subject to become blurry and become unnoticeable to the audience who is seeing the image or photo. It is one of the fundamental skill of the Photography, It serves us the eye of the photography. 

I hope this helps you in your Photography. 
Have a Nice Day. :)