\setlength{\unitlength}{0.007in}%
\begin{picture}(465,294)(15,400)
\thicklines

\put( 15,549){\makebox(0,0)[lb]{$y_s$}}
\put( 15,540){\vector( 1, 0){ 60}}
\put( 65,545){\makebox(0,0)[lb]{\twltt +}}
\put( 80,540){\circle{10}}
\put( 80,460){\vector( 0, 1){ 75}}
\put( 85,520){\makebox(0,0)[lb]{\twltt -}}
\put( 85,540){\vector( 1, 0){ 45}}


\put(130,520){\framebox(60,40){}}
\put(153,535){\makebox(0,0)[lb]{$c$}}
\put(190,540){\vector( 1,0){45}}

\put(203,545){\makebox(0,0)[lb]{$u$}}
\put(225,525){\makebox(0,0)[lb]{\twltt +}}
\put(240,540){\circle{10}}
\put(240,600){\vector( 0,-1){ 55}}
\put(235,615){\makebox(0,0)[lb]{$d$}}
\put(245,550){\makebox(0,0)[lb]{\twltt +}}
\put(245,540){\vector(1,0){45}}

\put(290,520){\framebox(60,40){}}
\put(313,535){\makebox(0,0)[lb]{$g$}}

\put(350,540){\vector( 1, 0){ 45}}
\put(393,615){\makebox(0,0)[lb]{$d_{ys}$}}
\put(400,600){\vector( 0,-1){ 55}}

\put(385,525){\makebox(0,0)[lb]{\twltt +}}
\put(400,540){\circle{10}}
\put(405,550){\makebox(0,0)[lb]{\twltt +}}

\put(405,540){\vector( 1, 0){ 65}}

\put(440,540){\line( 0,-1){ 80}}
\put(440,460){\line(-1, 0){360}}
\put(440,540){\circle*{4}}


\put(475,547){\makebox(0,0)[lb]{$y$}}

%\put(200,540){\vector( 1, 0){ 60}}
%\put(350,600){\framebox(60,40){}}
%\put(380,690){\vector( 0,-1){ 49}}
%\put(385,685){\makebox(0,0)[lb]{$d$}}
\end{picture}