Forward and Backward Moving Numbers
In the great Treatise there is mention of forward and backward moving numbers. Initially this seemed to relate to planets moving direct and retrograde, however there is another consideration that is likely. It is one that confirms the sequence of the hexagrams.
When viewing the correct sequential numbers of the hexagrams, this is a confirmation about the sequence. (This is not referring to the commonly accepted numbering in pairs of opposites as arranged by the Duke of Chou or King Wan which has no cyclical validity.)
From the winter solstice, moving towards the summer solstice, as the light increases, so do the numbers from 32 to 63. From the summer solstice, moving towards the winter solstice, as the light decreases, so do the hexagram numbers, from 31 to 0. 0 is the number for the Receptive, Mother Earth, and 63 is the number for the Creative, Heavenly Father. Light increases and then it decreases.
Out of the greatest darkness light emerges and after the greatest brightness the light recedes until it is total darkness again.
In the same way, the numbers move forwards away from the winter solstice and then backwards to the winter solstice.
In this interpretation, the degrees of the zodiac move from the bottom of the hexagram to the top, for 45 degrees, through the cardinal and first half of the fixed signs. From the middle of the fixed signs, for 45 degrees, to the end of the mutable signs, the degrees move from the top of the hexagram to the bottom. This could also be considered as backward and forward moving numbers.