\begin{frame} \frametitle{Example Transaction} \begin{center}\vspace{-6ex} \includegraphics[width=3cm]{images/creditcards.jpg} \end{center}\vspace{-3ex} A withdrawal of $100$ euro causes the ATM to perform a \emph{transaction in the bank's database}. \medskip \begin{exampleblock}{ATM Transaction} $\var{balance} \set \fun{read}(\var{account})$\\ $\var{balance} \set \var{balance}-100$\\ $\fun{write}(\var{account}, \var{balance})$\\ \end{exampleblock} \pause\bigskip The account is properly updated to reflect the new balance. \end{frame}