At the highest point of complete junction of the opposite edges, the colours appear as follows ([216]):—
| Yellow-red. | Blue. |
| Green. | Red. |
| Blue-red. | Yellow. |
Where the junction is less complete, the appearance is as follows ([214], [215]):—
| Yellow-red. | Blue. |
| Yellow. | Blue-red. |
| Green. | Red. |
| Blue. | Yellow-red. |
| Blue-red. | Yellow. |
Here, therefore, the surface still appears completely coloured, but neither series is to be considered as an elementary series, always developing itself in the same manner and in the same degrees; on the contrary, they can and should be resolved into their elements; and, in doing this, we become better acquainted with their nature and character.