With the interaction of the dynamic forces of creation, Yin and Yang, comes the Four Images 四象, or the four phases of universal energies. With this, the four cardinal directions are created: North, South, East and West.
These are formed by adding a Yin and a Yang line respectively on top of the Yin and Yang - creating a Major Yin （太阴） with two Yin lines, Minor Yin （少阴） with a Yin line at the bottom and Yang line on top, Minor Yang （少阳） with a Yang line at the bottom and Yin line on top, and Major Yang （太阳） with two Yang lines.
And from the Four Images or Four Phenomenon, eight phases of universal energy are developed, also known as the 八卦 or Eight Trigrams. These adds more granularity to the evolution of the energy, and with this, eight directions are created: North, South, East West, North-East, North-West, South-East, and South-West.
These are formed by adding a Yin and a Yang line respectively on top of the Four Images - creating the Eight Trigrams as shown in the summary image attached. Kindly note that development of the Four Images and Eight Trigrams should be viewed from bottom-up and not top-down.
