It involves two aspects: one is the form in "time" and the other is the form in "space".

Time form is called "music form", and another structure is "space".

The types of texture forms in two kinds of polyphonic music are:

1. Contrastive polyphony: If each voice combined at the same time has an independent and contrasting melody and rhythm, it constitutes a writing method of contrasting polyphony.

2. Imitate polyphony: The main melody appears in one voice and then in another, and each voice appears in turn with a certain delay. That is, other parts reproduce the melody of the first part (the first part) with different accuracy.