Fill a polar plot?

[matalog]

If I was to ask you how to fill a circle, would you also give me some examples of how to get a circle to fill a screen?

I mean, is there a way to fill the inside of a closed polar plot, with colour, or shading? If it was a circle that was drawn, then the circle would be filled with blue, for example, and the background of the graph, would be white.