I was trying some pm3d plots with the new 4.0 version when I
realized that yrange doesn't behave in the right way. If i try this:
>set pm3d map
>set yrange [0:2]
I get an y axe pointing downwards instead that upward (I mean y
values are increasing downward not upward). If you
try change yrange before plotting the bug doesn't arise. Further if
you try other style (not the map one) the bug doesn't arise too.