This program draws the result of applying a complex function to a circle radius $r$
in the complex plane, that is all points of the form $z=r e^{i \phi}$.
For a polynomial of degree $d$ and large values of $r$ this will produce a curve which loops $d$ times round the origin.
For small values of $r$ when the constant and linear terms dominate it will
be a small loop winding once round the constant term.

Jep is
a mathematical equation parsing and evaluation library written in
java. It features fast evaluation, a configurable architecture
allowing custom syntax, support for BigDecimal, complex numbers and
vectors It is developed by Singular
Systems

GWT-Jep is a port of Jep to run in javascript and has all the
features of Jep apart from a small set of changes
necessary for javascript compatibility. It is compiled from Java using
the Google Web
Toolkit. It is available as a seperate package from SingSurf.