Hi,
When I see a circle, I can imagine a relationship between people.
I think we Japanese always think about it and have an image of circle unconsciously.
And also it important when we communicate with others because as you know, Japan is high context culture country compared with other countries such as America.
When we talk each other, we really care about relationship or connection every time and try to build good one, while people who are in low context culture don't care so much about it and even it is meaningless for them.
I think what one imagine from a circle is related with one's custom( which can be affected by one's religion, culture, or environment) Circle is circle but circle is seen differently from people to people. it is very interesting to see the difference of things that people imagine from a circle.