This concept is coming from improvisations that are of songs that are used for dancing, and somehow not very slow dancing.
The idea is that when we sing and dance, usually the steps with the feet are more or double as many as the notes of the song in the voice.
So we utilize as refinement or filling of the melody with "dancing steps" up and down on the scale around the note of similar pattern as the dancing steps left and right (or back and forth) of the particular dance!
See also the post 347 about cloud statistical or probabilistic improvisation which is similar concept.
Τhe horizontal concept of threechords and tetrachords to create a melody as "dancing in tetrachord around the longer lasting notes" ( about one for each chord) is an alternative to the old fashioned idea of a small melodic theme and then variatiions by translation, inversion and elognation
