TikZ Kellerautomat, Beispiel: http://i.imgur.com/UfTfXl9.png

example.tex

\begin{tikzpicture}
    \begin{scope}[start chain, node distance=-0.15mm]
        \node [tmtapehend] (inputbegin) {};
        \node [tmtape] {$a_1$};
        \node [tmtape] {$a_2$};
        \node [tmtape, minimum width=2\tmtapesize] {$\ldots$};
        \node [tmtape] (inputcursor) {};
        \node [tmtape, minimum width=2\tmtapesize] {$\ldots$};
        \node [tmtapehend] (inputend) {};
    \end{scope}

    \begin{scope}[start chain=going below, node distance=-0.15mm]
        \node [tmtapevend, below=1cm of inputend] {};
        \node [tmtape] (stackcursor) {$D$};
        \node [tmtape] {$C$};
        \node [tmtape] {$B$};
        \node [tmtape] {$A$};
        \node [tmtape] (stackend) {$\#$};
    \end{scope}

    \node [tmtapecursor] (inputcursor) at (inputcursor) {};
    \node [tmtapecursor] (stackcursor) at (stackcursor) {};

    \node [draw, align=center, inner sep=3mm] (control) [left=2cm of stackcursor] {endliche Kontrolle\\(Zustand)};
    \node [align=center, font=\scriptsize, inner sep=0pt, above=2mm of inputcursor] {Lesekkopf, bewegt\\sich nach rechts};
    \node [align=left, font=\scriptsize, inner sep=0pt, right=2mm of stackcursor] {Lesekkopf, steht immer auf\\dem obersten Kellersymbol};

    \node [inner sep=0pt, above right=2mm and -\tmtapesize of inputbegin] {Eingabeband};
    \node [inner sep=0pt, below=3mm of stackend] {Keller};

    \begin{scope}[->, >=stealth', shorten >=1pt, auto]
        \draw (control) edge (stackcursor);
        \draw (control.north) -- ++(0,0.75) -| (inputcursor);
    \end{scope}
\end{tikzpicture}

style.tex

\newlength{\tmtapesize}
\setlength{\tmtapesize}{9mm}
\tikzset{tmtape/.style={
        draw,
        minimum size=\tmtapesize,
        inner sep=0,
        text height=1.8ex,
        text depth=0.25ex,
        on chain
    }
}
\tikzset{tmtapehend/.style={
        minimum size=\tmtapesize,
        line width=0pt,
        on chain,
        append after command={
            (\tikzlastnode.north west) edge (\tikzlastnode.north east)
            (\tikzlastnode.south west) edge (\tikzlastnode.south east)
        }
    }
}
\tikzset{tmtapevend/.style={
        minimum size=\tmtapesize,
        line width=0pt,
        on chain,
        append after command={
            (\tikzlastnode.north west) edge (\tikzlastnode.south west)
            (\tikzlastnode.north east) edge (\tikzlastnode.south east)
        }
    }
}
\tikzset{tmtapecursor/.style={
        minimum size=\dimexpr\tmtapesize+2mm,
        draw=maincolor,
        rounded corners=1mm,
        fill=maincolor,
        fill opacity=0.1
    }
}