\documentclass[pstricks]{standalone}
\usepackage{pst-marble}
\begin{document}
\begin{pspicture}(-6,-6)(6,6)
 \psMarble[
   colors={
     [0.20 0.10 0.02]
     [0.72 0.49 0.41]
   },
   viscosity=1000,
   oversample=2,
   actions={
     0 0 384 colors 1 get drop
     -192 0 288 colors 0 get drop
     -192 0 144 colors 1 get drop
     -192 0 56 colors 0 get drop
     180 [ -480 80 480 {} for ] 4 150 50 rake
     0 [ -520 80 520 {} for ] 4 150 50 rake
     -90 [ -480 80 480 {} for ] 4 150 50 rake
     90 [ -520 80 520 {} for ] 4 150 50 rake
     0 0 [ 75 150 225 300 375 ] 4 -120 50 stir
     0 0 -15 turn
   },
   shadings={
     0 0 -75 0 20 wriggle-shade
   }
 ](12,12)
\end{pspicture}
\end{document}