\SUBTRACT{\numberGOLD}{1}{\midaB}
\COPY{1}{\midaA}
\ADD{\midaA}{\midaB}{\Mida}
\setlength{\unitlength}{5cm}
\newcommand{\espiral}{%
    \Put(0,0){\begin{Picture}(0,0)(0,0)
      \translateorigin(\midaA,0)
      \pictcolor{red}
      \circularArc{\midaA}{\numberHALFPI}{\numberPI}
      \pictcolor{blue}
      \xLINE(0,0)(0,\midaA)
   \end{Picture}
   }
   \COPY{\midaA}{\Mida}
   \COPY{\midaB}{\midaA}
   \SUBTRACT{\Mida}{\midaA}{\midaB}
   \translateorigin(\Mida,\midaB)
   \changereferencesystem(0,\midaA)(0,-1)(1,0)
}
\renewcommand{\defaultplotdivs}{2}

\begin{center}
\begin{Picture}(0,0)(\numberGOLD,1)
   \Polygon(0,0)(\Mida,0)(\Mida,1)(0,1)
   % Plot 8 circular arcs
   \espiral\espiral\espiral\espiral
   \espiral\espiral\espiral\espiral
\end{Picture}

Golden rectangles and spiral
\end{center}
