The triads are spaced a whole tone apart with the scheme being ascending / descending in an upwards direction for 2 octaves, then ascending / descending back down.
Each inversion is presented in four groupings, as each measure is a Major Third apart, thus dividing the octave into 3 equal parts. Therefore, the triads repeat after the fourth grouping.
Triads are one of the more basic tools in an improviser's arsenal. A good technical facility, as well as a basic theoretical understanding of their usage both in and of themselves as well as their use as chordal extensions or upper structures, is an important part of building vocabulary.
Two Major triads a whole step apart are found diatonically in the Major and Melodic Minor scales (on the fourth and fifth degrees of each).
This exercise is but a starting point, as triad exercises can be built in half steps, thirds, etc., changing direction, Major, minor, mixed quality, etc., and all with inversions.
That should keep us all out of trouble, at least for a while, anyway.