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:

**Possible combinations:**

SBTA

SATB

ASBT

ATBS

TASB

TBSA

BTAS

BSAT

Circle *c1* resumes 8 possible combinations. Here is how we use it:

- We can start in any voice (S = soprano, A = alto, T = tenor and B = bass).
- Once we have selected a voice we can move along the circle in any direction.

**Possible combinations:**

STAB

SBAT

ABST

ATSB

TABS

TSBA

BSTA

BATS

**Possible combinations:**

SABT

STBA

ABTS

ASTB

TSAB

TBAS

BTSA

BAST

**Possible combinations:**

SBA

SAB

ASB

ABS

BAS

BSA

We propose the following method for naming the various combinations:

- We first identify the circle:
*c1* - Followed by the voice:
*c1b*means we will use the circle*c1*, beginning with the bass. - Finally the direction, + clockwise direction, - counterclockwise direction. For example: c1b+ means c1, beginning with the bass in clockwise direction.