I have quillows lows in the car very useful. I have made 2 different styles.
A . The typical one joined on 3 sides to make the pillow on the back.
B. I made quilts for young nephews who go camping with their parent who are scout leaders. Idea was for extra warmth. The cushion on the back I placed tabs in the middle of 3 sides and joined tabs onto quilt this method left the corners open. The 3 year old said it was easier to fold up.