Polar plots are generated by changing the current coordinate system to
polar before issuing a plot command. The option set polar tells gnuplot to
interpret input 2D coordinates as 4#4angle5#5,4#4radius5#5 rather than 4#4x5#5,4#4y5#5.
Many, but not all, of the 2D plotting styles work in polar mode.
The figure shows a combination of plot styles lines and filledcurves.
See set polar (p. ), set rrange (p. ), set size square (p. ), set theta (p. ), set ttics (p. ).