# TikZ does not use square coordinates but polar one, how to change it in order to use Cartesian coordinates?

Consider the following:

\begin{tikzpicture}[thick,scale=0.8]
\node  (v0) at (0,0) [label=right:$\emptyset$] {};
\node (v1) at (40:-2)  [label=right:$v_1$] {};
\node (v2) at (70:-1.6)  [label=right:$v_2$] {};
\node (v3) at (110:-1.6)  [label=right:$v_3$] {};
\node (v4) at (140:-2)  [label=right:$v_4$] {};
\node (v5) at (50:-3.5)  [label=right:$v_5$] {};
\draw  (v0)  --  (v1)
(v0)  --  (v2)
(v0)  --  (v3)
(v0)  --  (v4)
(v1)  --  (v5);
\end{tikzpicture}

Here coordinates are polar. How to use square?

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What do you mean? The first (0,0) you have for (v0) is in "square" coordinates (i.e. "cartesian coordinates")? –  mathematical.coffee Mar 9 '12 at 6:15