A cylindrical charge distribution embedded into a cylindrical dielectric with chi=1. Negative charge is shown in blue, positive charge in red.  The pale color circles represent the induced charge.  Although inducted charge is located at surface of a dielectric, it is drawn in the nearest grid cell  and may appear to be outside the dielectric.

Note:  Calculations with dielectrics may converge slowly.  Increase the value of chi and notice the value at which the calcuation does not converge.  Both the accuracy and the maximum number of calculations can be set using JavaScript.