\begin{frame}
  \frametitle{Symmetry}

  \begin{exampleblock}{}
  How to remember what is even and odd?
  \end{exampleblock}
  \bigskip\pause
  
  \begin{minipage}{.49\textwidth}
  \begin{center}
  {\small $x^2$}\scalebox{.5}{
  \begin{tikzpicture}[default,baseline=1cm]
    \diagram{-2}{2}{-1}{3}{1}
    \diagramannotatez
    \diagramannotatex{-1,1}
    \diagramannotatey{-1,1}
    \draw[cred,ultra thick] plot[smooth,domain=-1.75:1.75,samples=20] (\x,{pow(\x,2)});
  \end{tikzpicture}
  }
  \end{center}
  \end{minipage}
  \begin{minipage}{.49\textwidth}
  \begin{center}
  {\small $x^4$}\scalebox{.5}{
  \begin{tikzpicture}[default,baseline=1cm]
    \diagram{-2}{2}{-1}{3}{1}
    \diagramannotatez
    \diagramannotatex{-1,1}
    \diagramannotatey{-1,1}
    \draw[cred,ultra thick] plot[smooth,domain=-1.32:1.32,samples=20] (\x,{pow(\x,4)});
  \end{tikzpicture}
  }
  \end{center}
  \end{minipage}
  \medskip

  \begin{minipage}{.49\textwidth}
  \begin{center}
  {\small $x^3$}\scalebox{.5}{
  \begin{tikzpicture}[default,baseline=0ex]
    \diagram{-2}{2}{-2}{2}{1}
    \diagramannotatez
    \diagramannotatex{-1,1}
    \diagramannotatey{-1,1}
    \draw[cblue,ultra thick] plot[smooth,domain=-1.27:1.27,samples=20] (\x,{pow(\x,3)});
  \end{tikzpicture}
  }
  \end{center}
  \end{minipage}
  \begin{minipage}{.49\textwidth}
  \begin{center}
  {\small $x^5$}\scalebox{.5}{
  \begin{tikzpicture}[default,baseline=0ex]
    \diagram{-2}{2}{-2}{2}{1}
    \diagramannotatez
    \diagramannotatex{-1,1}
    \diagramannotatey{-1,1}
    \draw[cblue,ultra thick] plot[smooth,domain=-1.15:1.15,samples=20] (\x,{pow(\x,5)});
  \end{tikzpicture}
  }
  \end{center}
  \end{minipage}
  
  \begin{exampleblock}{}
    Thick of \emph{power functions $x^n$} with $n$ a natural number:
    \begin{itemize}
      \item $x^n$ is even if $n$ is even
      \item $x^n$ is odd if $n$ is odd
    \end{itemize}
  \end{exampleblock}
\end{frame}