I challenge you to go to a local store and photograph shopping carts. You will find lines, areas, plastic, metal etc. When I started I thought it might get boring but I was surprised how many cool images you can get photographing shopping carts.
These carts were stacked together. There are many beautiful lines in this images and I decided that on the left hand side the lines go through the corners.
Enjoy and have fun and by the way don’t be surprised if people ask you what you are doing? Some people might be wondering why you are photographing shopping carts.