After the Four Symbols (xiang) produce the Eight Diagrams (Ba Gua), the Eight Diagrams interact to produce the Canon of 8 x 8 = 64 Changes (I Ching). By crossing or combining each of the Eight Diagrams (Ba Gua) with itself and each of the others, all possible combinations of Change are represented.
Recall that Three Operations produce akasha, upon which all matter and phenomena depend. Given akasha, a world and everything in it can be modeled, but we are left with just a static model -- a dead world. To create a real world, we require Change. To account for Change, we require a second model to represent the outcome of the Change.
In another discussion of Change, we suggested that vectors or paths between corners of the Ba Gua hypercube could be used to represent Change. The option to juxtapose two individual Gua (trigrams: three-line figures) is simply an explicit presentation of the finished state, rather than using a vector to suggest the approached state. Given the notation in the figure at top, we can represent movement from (1,1,1) --> (0,1,1) with an arrow pointing from the first corner to the second as just shown, or simply enumerate it as (111,011). This interaction between two of the Eight Diagrams produces Change #9, Small Harvest. The remaining sixty-three Changes may be likewise produced.
By opposing an inner or initial situation with a second final or outer situation, a Change is produced. We have now accounted for the three dimensions of space and the fourth temporal dimension (as represented by Change).