Labeling cube vertices with trigrams and Cartesian coordinates
The vertices have first been labeled with a letter (t=top; b=bottom) and a number (1, 2, 3, or 4) for easy identification and reference.
Next the eight trigrams are positioned, one at each of the eight vertices as follows:
b1 ☷ EARTH t1 ☵ WATER
b2 ☶ MOUNTAIN t2 ☴ WIND
b3 ☲ FIRE t3 ☰ HEAVEN
b4 ☳ THUNDER t4 ☱ LAKE
Now let the side of the cube equal two units.
Let the center of the cube be located at Cartesian coordinate (0,0,0).
Let yang = +1 and yin = -1.
Let the first (bottom) line of a trigram represent the x dimension (left/right), directed from right (-) to left (+).* Let the second (middle) line of a trigram represent the y dimension (up/down), directed from bottom (-) to top (+). Let the third (top) line of a trigram represent the z dimension (forward/backward), directed from closer to the viewer (-) to farther from the viewer (+).**
*This is opposite the Western convention but will make no difference as will be shown in the post to follow.
**The y and z dimensions have been interchanged here relative to the Western convention. These changes preserve certain prepotent associations between the trigrams and their compass points in the I Ching. In any diagram or display, the orientation of the three axes, as a whole, is arbitrary. However, the orientation of the axes relative to each other should always comply with the right-hand rule, unless specifically stated otherwise. All laws of physics and math assume this right-handedness, which ensures consistency. The orientation described here does in fact comply with the right-hand rule.