Let's say we have one simple box and its bottom has been cut in a circular shape. We want to attach another box to this box that can rotate 180deg around the first one. What mechanism can be used to join these two boxes?
Perhaps a "turntable bearing" also called a "lazy susan" bearing. Something like this one: https://www.amazon.com/Square-Inch-Susan-Turntable-Bearing/dp/B00ZSQSWTM