The system of classification of 3 and 4 voices fugues according to the order of voice entries in the expositions we propose summarizes all possible combinations using simple circles like the following ones.
For 4 voices fugues:
For 3 voices fugues:
How do they work? They all work in the same way. We'll use circle c1 as example:
Circle c1 resumes 8 possible combinations. Here is how we use it:
We propose the following method for naming the various combinations: