I'm trying to decorate a snake path, but I don't get any output using a postaction. Here's the example code.
\begin{tikzpicture}
\draw [snake=expanding waves, segment amplitude = 1.5cm, segment length = 0.3 cm, postaction={decorate, decoration={random steps,segment length=3pt,amplitude=5pt}}] (0,0) -- (-2,0);
\end{tikzpicture}
Any help would be greatly appreciated.