set pm3d explicit
set palette rgbform 9,8,9
set parametric
set urange [0:2*pi]
set vrange [-pi:pi]
set isosamples 36,24
set hidden3d
set view 75,15,1,1
unset key
set ticslevel 0
x1(u,v)=cos(u)+.5*cos(u)*cos(v)
y1(u,v)=sin(u)+.5*sin(u)*cos(v)
z1(u,v)=.5*sin(v)
x2(u,v)=1+cos(u)+.5*cos(u)*cos(v)
y2(u,v)=.5*sin(v)
z2(u,v)=sin(u)+.5*sin(u)*cos(v)
set term png transparent xffffff 
set output "graph_ex2.png"
set multiplot
splot x1(u,v), y1(u,v), z1(u,v) w pm3d, \
      x2(u,v), y2(u,v), z2(u,v) w pm3d
splot x1(u,v), y1(u,v), z1(u,v) lt 3,\
      x2(u,v), y2(u,v), z2(u,v) lt 5
unset multiplot
!convert -geometry 30% -colors 512 graph_ex2.png graph_ex2s.png