set pm3d depth lighting primary 0.65 specular 0.1
set object rect from sc 0,0 to sc 1,1 behind fc "#003344"
set palette defined (0 "#669966", 1 "#ff9966")
set samples 128
set isosamples 128
unset border
unset tics
unset colorbox
unset key
set xyplane 0
set view 30,55, 1.6,1.6
set term pngcairo size 360,360
set out "snail.png"

set parametric
set urange [0:2*pi]
set vrange [-pi:pi]
c = 2*pi
set xrange [-c:c]
set yrange [-c:c]
set zrange [-c:c]
x(u,v) = u*cos(u)*cos(v)
y(u,v) = -u*sin(v) 
z(u,v) = u*sin(u)*cos(v)

splot x(u,v), y(u,v), z(u,v) w pm3d
!display  "snail.png"