ps-estructure de politja

\begin{ps-estructure}
\case{(-1)}
{
\caixa{not(x-m),y-m}{m_{1}}
\corda{0+(-r),y}{not(x-m),y-m}
\vector-vertical-negatiu{not(x-m),y}{q_{1}·g}
\vector-vertical-positiu{not(x-m),y}{T_{1}}
}
\case{not(0)}
{
\semi-cercle-negatiu{not(not(0)),y}{r}
\vector-vertical-negatiu{not(not(0)),y}{q_{0}·g}
}
\case{0}
{
\semi-cercle-positiu{0,y}{r}
\vector-vertical-positiu{0,y}{F_{0}}
}
\case{1}
{
\caixa{x-m,y-m}{m_{2}}
\corda{0+r,y}{x-m,y-m}
\vector-vertical-negatiu{x-m,y}{q_{2}·g}
\vector-vertical-positiu{x-m,y}{T_{2}}
}
\end{ps-estructure}