Shift some items of enumerate

Question

I have enumerate in a slide, I would like the beginning, including the bullet, of the 2nd and the 3rd \item shift a little bit on the right, compared to the 1st \item:

Item1
  Item2
  Item3

Does anyone know how to do this?

Answer 1

Here's a possible solution using nested enumerate environments and a redefinition of the enumerate subitem template to use the counter for the first level:

\documentclass{beamer}

\begin{document}

\begin{frame}

\begin{enumerate}
\item First item.
  \setbeamertemplate{enumerate subitem}{\insertsubenumlabel.\stepcounter{enumi}}
  \begin{enumerate} 
  \stepcounter{enumii}
  \item Second item.
  \item Third item.
  \end{enumerate}
\item Fourth item.
\end{enumerate}

\end{frame}

\end{document}

For the case of items with balls:

\documentclass{beamer}
\usetheme{Boadilla}

\begin{document}

\begin{frame}

\begin{enumerate}
\item First item.
\setbeamertemplate{enumerate subitem}
{
  \begin{pgfpicture}{-1ex}{-0.55ex}{1ex}{1ex}
    \usebeamercolor[fg]{subitem projected}
    {\pgftransformscale{1.75}\pgftext{\normalsize\pgfuseshading{bigsphere}}}
    \pgftext{%
      \usebeamerfont*{subitem projected}%
      \insertsubenumlabel\stepcounter{enumi}}
  \end{pgfpicture}%
}
  \begin{enumerate} 
  \stepcounter{enumii}
  \item Second item.
  \item Third item.
  \end{enumerate}
\item Fourth item.
\end{enumerate}

\end{frame}

\end{document}

Answer 2

I believe this should work with any style, but it does move only the first line of the item:

\documentclass{beamer}

\begin{document}

\begin{frame}

\begin{enumerate}
\item First item.
\addtolength{\itemindent}{1cm} % move right
\item Second item.
\item Third item.
\addtolength{\itemindent}{-1cm} % move left
\item Fourth item.
\end{enumerate}

\end{frame}

\end{document}