\documentclass[pstricks]{standalone}

\usepackage{pst-fourbarlinkage,multido}


\begin{document}
\multido{\i=0+10}{73}{
\begin{pspicture}(-8,-8)(10,8) % class 18
\psFourBarLinkage[unit=1,barlengths=14 14 10 10,N=\i,fixedcentrodes,centrodes,Nmax=720,dmax=5] % classe 18
\end{pspicture}}
\end{document}