I want to draw a plot with the points:

y >= f(x)

where f(x) is some function I define.

Using an x-y plot, I can draw only the function:

y = f(x)

Using an area plot, I can draw an area of a single column (i.e. not y as a function of x). Is there any way I can fill the area above the x-y curve?

EDIT: When the x values are linear (i.e. 0, 1, 2, ...) then it is easy to fill the area below the curve by using an area plot with the y series only, like here (right):