Round items give a playful effect and help you to break the clean lines.
You can hang the wall circle with, for example, double-sided tape for the inside. Make sure you choose the tape that is suitable for your wall. There is no borehole in the wall circle, you can possibly drill a hole yourself and hang the wall circle with a screw. You can also place the circle on a wall board or dresser.
The wall circles are made of Forex, a light material that is hard and sturdy. Forex has a foam core inside, with a hard white top layer. Forex is suitable for indoor use, not outdoor use.