I'm drawing a multi-segment line with TikZ as below:
\begin{figure*}
\center
\begin{tikzpicture}
\draw[->] (0.25,0) --(0.75,1.2) -- (1.25,1.5) -- (1.75,0.7) -- (2.25,1.1) -- (2.75,0.5) -- (3.25,1.5) -- (4.25,1.8);
\end{tikzpicture}
\end{figure*}
I'd like a few of the segments of the line to be thick, and the rest to be thin. Or, put another way, I'd like the line to be thick from (0.25,0) up until (1.75,0.7).
If I just do \draw[thick] ... the whole line becomes thick, which is not what I want.
Any thoughts?
Thanks!

to[]blocks with--connections. – Richard Apr 11 '12 at 16:46