f(x,y)=-x**3+3*x*y-y**3
#
set style line 100 lw 0.1 lc rgb "steelblue"
set pm3d depth hidden3d ls 100
set cbrange [-4:2]
set palette rgb 7,7,3
set view 60,80
set samples 50
set isosamples 50
set ticslevel 0
splot [-3:3][-3:3] f(x,y)<-3 ? -3 : f(x,y)>1 ? 1: f(x,y) lt 2 w pm3d
pause 3
set term pngcairo size 480,480
set out "nose.png"
replot