# Undefined Control Sequence due to TikZ-Tokens

I have a question concerning this minimal example:

\documentclass{minimal}
\usepackage{tikz}
\usetikzlibrary{petri}

\begin{document}
\begin{tikzpicture}
\node[place, tokens=2] (p) {};
\end{tikzpicture}
\end{document}


This gives me the following two errors:

! Undefined control sequence.
\pgfutil@font@tiny ->\tiny

l.8     \node[place, tokens=2] (p) {};

?
! Undefined control sequence.
\pgfutil@font@tiny ->\tiny

l.8     \node[place, tokens=2] (p) {};

?


If I set tokens=3 I'll get accordingly the error three times, if I remove the tokens, everthing is fine. Can anyone, please, at lest tell me where to look for the error?

-

This happens because the minimal class doesn't define font sizes like \tiny. You should use article or some other "normal" class instead.
Errors like this are the reason why it is generally not recommended to use the minimal class for minimal working examples.