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 24
unset border
unset tics
unset colorbox
unset key
set xyplane 0
set view 30,0, 1.8, 1.8
set term pngcairo size 360,360
set out "torus-knot.png"
set parametric
set urange [0:2*pi]
set vrange [0:2*pi]
r = 0.08
R1 = 1
R2 = 0.15
p = 5
q = 3
c = R1 + R2 + r
set zrange [-c:c]
set xrange [-c:c]
set yrange [-c:c]

x(u,v) = (R1 + R2*cos(p*u) + r*cos(v))*cos(q*u)
y(u,v) = (R1 + R2*cos(p*u) + r*cos(v))*sin(q*u)
z(u,v) = r*sin(v) + R2*sin(p*u)

splot x(u,v), y(u,v), z(u,v) w pm3d

!display "torus-knot.png"