set parametric
set pm3d
unset key
set palette rgb -10,-4,0
set samples 200
set cbrange[-0.5:0.5]
set vrange[0:2*pi]
set urange[0:2*pi]
set size square
w=0.015
set term png transparent xffffff
set out "flower.png"
splot (0.5+cos(5*u))*cos(2*u),\
       (0.5+cos(5*u))*sin(2*u), \
      0.5*(cos(5*u)-0.3*cos(15*u)+0.2*cos(25*u)) lw 3 palette 
!convert -geometry 50% -colors 256 flower.png flower_s.png
!display flower_s.png
pause -1