In Zen the 'enso' ("circle") is a disciplined creative practice. Traditionally it is painted in a single stroke using hand-ground, carbon based ink on rice paper. There is no formula, no correct form, no mistakes are made. I associate enso painting with the Japanese appreciation of 'wabi-sabi' -- the beauty in imperfection. The circle may be open or closed. It's 'meaning' is not conceptual but, for lack of a better term, spiritual in that what is conveyed must be felt (or intuited) rather than thought. It's the walk of life.