\overlays{3}{
  \begin{slide}{Introduction}

    The \texttt{Prosper} class translates into two different formats:
    \begin{itemize}
    \item Adobe\textregistered\ \it{Postscript}\texttrademark
    \item Adobe\textregistered\ \it{Portable Document Format}
          \texttrademark\ (PDF)
    \end{itemize}

    The compilation process:\\
    \fromSlide*{1}{\fbox{\LaTeX}}%
    \fromSlide*{2}{$\rightarrow$ \fbox{DVI}}%
    \fromSlide*{3}{$\rightarrow$ \fbox{PostScript} or \fbox{PDF}}%
  \end{slide}
}