This surface was first discussed by Hoffman and Karcher. It shows the attempt to make an embedded minimal sphere with three ends. The two catenoidal ends are parallel catenoid ends, but the planar end must necessarily intersect the two other ends, because, by the theorem of López and Ros, such a surface cannot be embedded.
Taiji, the "Supreme Ultimate" state of undifferentiated absolute and infinite potential is the oneness before duality; from here Yin and Yang originate. (Guide to the I Ching, China's most popular means of divination)