Upper trigram
☱
Lake · Dui
Joy and openness.
FamilyYoungest daughter
ElementMetal
Hexagram 43 of 64
☱☰ Breakthrough
A resolute push past resistance.
Lower trigram
☰
Heaven · Qian
Creative force.
FamilyFather
ElementMetal
The image
Lake above, Heaven below.
Lake over Heaven: joy and openness meeting creative force.
That combination is the whole meaning of hexagram 43. 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.