Polynomiography of Newton method for one parameter cubic polynomial

Generation of the polynomiography of the Newton's method for the one parameter cubic polynomial

This code permits us to generate the polynomiography
of the Newton's method for the one parameter cubic polynomial p(z)=
z^3+(c-1)*z-c, where c is the parameter space
We first check that 0 is a free critical point of Newton method
for the polynomial p(z)