Flip an Array Over 45 degree Axis

I need to flip this plot(only the blue line) over a 45 degree axis so that the part of the parabola touching the x axis will be then plotted on the y axis, and the parabola edge touching the y axis will be on the x axis. I have no idea what is going wrong I have been trying everything from rotating to flipping to plotting y vs x instead. Any suggestions would be greatly appreciated.

[José-Luis]

Which plot?

Answer 1

[Image Analyst]

How about instead of

plot(x,y);

do

plot(y, x);