Upper trigram
☰
Heaven · Qian
Creative force.
FamilyFather
ElementMetal
Hexagram 13 of 64
☰☲ Fellowship
Shared purpose in open company.
Lower trigram
☲
Fire · Li
Clarity and attachment.
FamilyMiddle daughter
ElementFire
The image
Heaven above, Fire below.
Heaven over Fire: creative force meeting clarity and attachment.
That combination is the whole meaning of hexagram 13. Nothing about it is arbitrary — change either trigram and you get a different hexagram with a different reading, which is why the 64 form a system rather than a list.