To sktech the circles in the visualization, you need to use the paramteric equation of a circle (x = r cos (Θ), y = r sin(Θ). A circle can be shown as a polygon where the points of the polygon are formed using the parametric equation. Usually you let a parameter Θ vary from 0 to 2π (i.e. 0 <= Θ < 2π), plug Θ into the parametric equations and formed x,y points. Create line segments to join adjacent points of the circle.