a yellow square, indicating this line as the constituting ruler of the hexagram Six in the third place means:

When three people journey together,
Their number increases by one.
When one man journeys alone,
He finds a companion.

When there are three people together, jealousy arises. One of them will have to go. Avery close bond is possible only between two people. But when one man is lonely, he is certain to find a companion who complements him.