\documentclass[pstricks]{standalone}

\usepackage{pst-fourbarlinkage,multido}


\begin{document}
\multido{\i=0+10}{37}{
\begin{pspicture}(-4,-5)(6,4) % class 1
\psFourBarLinkage[unit=1.5,crossed=false,N=\i,connectedpoints=false,centrodes,fixedcentrodes,posM=1 0.5,barlengths=20 21 15 10] % classe 1 % 20 32 30 15
\end{pspicture}}
\end{document}