set pm3d depth lighting 
set object rect from sc 0,0 to sc 1,1 behind fc "#114400"
set palette defined (0 "#6666ff", 1 "#6666ff")
set samples 256
set isosamples 96
unset border
unset tics
unset colorbox
unset key
set xyplane 0
set view 45,60, 1.5, 
set term pngcairo size 360,360
set out "JK.png"
set parametric
set urange [0:2*pi]
set vrange [0:2*pi]
c = 3.5
set xrange [-c:c]
set yrange [-c:c]
set zrange [-c:c]

S = 2
T = 4
a = 1
W(u,v) = ((S+1)/4.0)*cos((S+1)*u + pi/T) + sqrt(a)
x(u,v) = S*cos(u) + cos(S*u) -W(u,v)*sin((S-1)*u/2)*cos(v)
y(u,v) = S*sin(u) - sin(S*u) -W(u,v)*cos((S-1)*u/2)*cos(v)
z(u,v) = W(u,v)*sin(v)

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

# http://www.3d-meier.de/tut3/Seite0.html
# Jeener-Klein