Spontaneous Formation of Mandalas

Somehow, I seem to be forming mandalas within my psyche without any particular knowledge of how I'm doing so. I'm merely walking around, or meditating, and there will occur mandalas of great complexity (usually of the same shape) which arise in my mind. When they do, my mind will explore and think about them, almost obsessively, and attempt to understand them. Any idea about this?