The flat surface is required because it is easier to post and lasts longer. If you want to stick it in the car or on the inner wall, you can use glass glue. However, it is not easy to transfer if you want to change it. You can go to the "Space" of my Taobao store "Art Specialty Store" Check out more than 2,000 varieties, including crystal relief, mirror, PVC, flat surface and other materials