Variations on the melodic-harmonic formula known by association with a popular refrain “Guárdame las vacas.” The formula is closely related to the Italian Romanesca, some argue identical. It is a question of minor metrical differences.
The central pattern Guárdame las vacas is the conjunction of melody and harmony, together, combined and inseparable:

melody mi re do si :| la
chords III VII i V :| i

see commentary for na032