009 Three Dimensional Number System
Observe the chart above. Imagine it as three floating tablets with the leftmost tablet in the front and the rightmost tablet in the far back.
The first ternary sub-digits appear under the flipped C symbols. The second ternary sub-digits appear in the center and the third ternary sub-digits appear above the flipped C symbols. These can be referred to as upper, middle and lower ternary sub-digits.
Notice now how all the first columns in each of the tablets have identical lower ternary sub-digits. We also see that all the rows across all three tablets have matching middle ternary sub-digits. And if we check the upper ternary sub-digits, we will find that all glyphs match on a particular tablet, but do not match between the tablets.
Another way to think about this:
Lower ternary digits specify horizontal positions (x axis)
Middle ternary digits specify vertical positions (y axis)
Upper ternary digits specify depth (z axis)