Just like a plant that grows bottom-up, a hexagram is built from bottom to top during consultation and lateron – specially at no2DO – read that way.
Although some other authors may not explicitly consider this sequencing, it is undisputed that the two core character reveal how lower and upper trigram interact. To me it just seems logical to match the way a hexagram is built and how it is lateron read (from bottom to top).
Interestingly enough, there is a specific order in the way individual trigrams evolve: each trigram has only two ways to transform itself into another trigram:
The dark arrow indicates that a (broken) yin line is added. The red arrow indicates that a (solid) yang line is added.
Hexagram 11 – Peace (shown in the animation above) would result in the following graphic: