\begin{frame}{Motivation} Computer is based on a \emph{universal computation mechanism}. \medskip \centerline{\includegraphics[height=13mm]{images/red-thread.jpg}} \pause\medskip What does \emph{universal} mean? \pause Roughly speaking, no other computation model can compute more. \pause\medskip \begin{goal}{} \emph{Turing machines} were invented in 1936 by Alan Turing: \begin{minipage}{.65\textwidth} \begin{itemize} \medskip \item abstract computation model \medskip \item \emph{automata} with read/write tape \medskip \item universal computation mechanism \medskip \end{itemize} \end{minipage}% \begin{minipage}{.34\textwidth} \begin{tikzpicture}[default,label/.style={rectangle,inner sep=1mm}] \aturing \end{tikzpicture} \end{minipage} \end{goal} \medskip Universal computation invented before the first computers! \end{frame}