\begin{figure}[htb]
\begin{center}
  \begin{picture}(200,90)(0,0)
    \put(0,20){\line(1,0){200}}
    \put(0,70){\line(1,0){200}}
    \put(100,20){\line(0,1){50}}
    \put(50,20){\circle{5}}
    \put(100,20){\circle*{5}}
    \put(150,20){\circle{5}}
    \put(100,70){\circle*{5}}
    \put(100,80){$u_{i,j+1}$}
    \put(50,80){$u_{i-1,j+1}$}
    \put(100,5){$u_{i,j}$}
    \put(150,80){$u_{i+1,j+1}$}
    \put(0,20){\circle{5}}
    \put(0,70){\circle{5}}
    \put(50,20){\circle{5}}
    \put(200,20){\circle{5}}
    \put(50,70){\circle*{5}}
    \put(150,70){\circle*{5}}
    \put(200,70){\circle{5}}
  \end{picture}
  \caption{Shema implicitne metode.}
  \label{slika3}
\end{center}
\end{figure}