Q:

Gnuplot filledcurves flip axes

There is a style to fill the space between two functions of x.
Examples of such plots can be found e.g. at http://gnuplot.sourceforge.net/demo/fillbetween.html
Is there any way to make similar plot, but with flipped x and y axes? 
Here is the desired shape of a curve (without rotated/mirrored labels, titles and legends, of course)...

It could be done with closed contour (like last example here http://www.gnuplot.info/demo_svg_cvs/fillcrvs.html), but this would require reshuffling the data file.  Any other options? 
Thank you! 

A:

You can't do this directly.  From help filledcurves:

The third variant fills the area between two curves sampled at the same set of
   x coordinates.   It requires three columns of input data (x, y1, y2). 

I don't think you can specify (y, x1, x2) directly.  As a workaround you can the area between the y axis and the larger function in some color, and then fill the area between the y axis and the smaller function in white:
x1(y) = cos(y)+1
x2(y) = cos(y)+2
xmax(y) = (x1(y) > x2(y) ?  x1(y) : x2(y))
xmin(y) = (x1(y) < x2(y) ?  x1(y) : x2(y))

plot '+' using (xmax($1)):1 with filledcurve y1, \
     '+' using (xmin($1)):1 with filledcurve y1 fillcolor rgb "white"

This probably has to be tweaked a little if one or both of the two functions can be negative.