**This is an old revision of the document!**
% Turing Machine % Author: Sebastian Sardina \documentclass[a4paper,10pt]{article} \usepackage{tikz} \usepackage[active,tightpage]{preview} \PreviewEnvironment{tikzpicture} \setlength\PreviewBorder{5pt}% \usetikzlibrary{chains,fit,shapes} \begin{document} \begin{tikzpicture} \tikzstyle{every path}=[very thick]
\edef\sizetape{0.7cm} \tikzstyle{tmtape}=[draw,minimum size=\sizetape] \tikzstyle{tmhead}=[arrow box,draw,minimum size=.5cm,arrow box arrows={east:.25cm, west:0.25cm}]
Draw TM tape \begin{scope}[start chain=1 going right,node distance=-0.15mm] \node [on chain=1,tmtape,draw=none] {$\ldots$}; \node [on chain=1,tmtape] {}; \node [on chain=1,tmtape] (input) {b}; \node [on chain=1,tmtape] {b}; \node [on chain=1,tmtape] {a}; \node [on chain=1,tmtape] {a}; \node [on chain=1,tmtape] {a}; \node [on chain=1,tmtape] {a}; \node [on chain=1,tmtape] {}; \node [on chain=1,tmtape,draw=none] {$\ldots$}; \node [on chain=1] {\textbf{Input/Output Tape}}; \end{scope} Draw TM Finite Control \begin{scope} [shift={(3cm,-5cm)},start chain=circle placed {at=(-\tikzchaincount*60:1.5)}] \foreach \i in {q0,q1,q2,q3,\ddots,q_n}
\node [on chain] {$\i$};
% Arrow to current state \node (center) {}; \draw[→] (center) – (circle-2);
\node[rounded corners,draw=black,thick,fit=(circle-1) (circle-2) (circle-3)
(circle-4) (circle-5) (circle-6),
label=below:\textbf{Finite Control}] (fsbox)
{};
\end{scope}
Draw TM head below (input) tape cell \node [tmhead,yshift=-.3cm] at (input.south) (head) {$q_1$}; Link Finite Control with Head \path[→,draw] (fsbox.north) .. controls (4.5,-1) and (0,-2) .. node[right]
(headlinetext)
{}
(head.south);
\node[xshift=3cm] at (headlinetext)
{\begin{tabular}{c}
\textbf{Reading and Writing Head} \\
\textbf{(moves in both directions)}
\end{tabular}};
\end{tikzpicture} \end{document}