  Stellarators commonly comprise different sets of coils to produce diverse
magnetic configurations. However, the diversity of possible configurations in a
single device is usually rather limited. The achievement of a broad variety of
magnetic configurations might be valuable for some purposes, for example, to
assay the effect of the magnetic configuration on turbulent transport. Thus, a
method is created to systematically define sets of modular coils located on
concentric toroidal winding surfaces. The method is based on the expression of
a Last Closed Flux Surface (LCFS) by Fourier coefficients in cylindrical
coordinates and consists in the definition of successive windings located on
equidistant concentric winding surfaces, each winding such that produces a
magnetic field which, when added to the magnetic field generated by a sole base
winding that generates a base magnetic configuration, produces a magnetic
configuration whose LCFS is defined by the Fourier coefficients of the base
magnetic configuration plus only one new Fourier coefficient. The utilization
of a diversity of currents in the different windings would give a linear
combination of magnetic fields that reproduce the LCFS defined mathematically
by the respective Fourier coefficients. The deviation between a particular
modelled LCFS and the obtained LCFS from the windings depends on: the order and
value of each Fourier coefficient, the selected shape of concentric winding
surfaces, and the possible intersection of the LCFS with the internal winding
surface. The method to generate the windings is reported and the application to
one case study is described. Each modelled LCFS is compared with the respective
Poincar\'e plot obtained from the linear combination of magnetic fields from
the windings.
