1. 4 on class

On grammatical class:

vi'a

dimensionality of space interval tense: 2-space interval; throughout an area.

vi'e

dimensionality of space interval tense: 4-space interval; throughout a spacetime.

vi'i

dimensionality of space interval tense: 1-space interval; along a line.

vi'u

dimensionality of space interval tense: 3-space interval; throughout a space.