The box series is a physical manifestation of a mental place that we all engage in. A box has four walls and a lid. It is a place to hold things safely, be it a bit of jewelry or a dream.
The danger is when we go inside our box with its four walls and a lid and forget to get out.
It becomes our cage and prison, but we stop seeing it for that and instead see everything on the outside as ominous and fearful.
Do not stay too long in your box.