Upper trigram
☰
Heaven · Qian
Creative force.
FamilyFather
ElementMetal
Hexagram 12 of 64
☰☷ Standstill
The inverse of Peace; forces moving apart.
Lower trigram
☷
Earth · Kun
Receptive yielding.
FamilyMother
ElementEarth
The image
Heaven above, Earth below.
Heaven over Earth: creative force meeting receptive yielding.
That combination is the whole meaning of hexagram 12. 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.