Create ellipse on the current plot
ellipse(xc = 0, yc = 0, a, b, col = "black", lty = 1, ...)
xc
: coordinate of center (x)yc
: coordinate of center (y)a
: major axisb
: minor axiscol
: color of the ellipse linelty
: type of the ellipse line...
: any argument suitable for lines
function