\usepackage{etex}
\usepackage{pgfpages}
\usepackage{color}
\usepackage{tikz}
\usetikzlibrary{shapes}
\usetikzlibrary{backgrounds}
% beamer mode
\mode<beamer>{
\usetheme{Warsaw}
}
% transparency mode
\mode<trans>{
\usetheme{Warsaw}
}
% handout mode
\mode<handout>{
\usetheme{default}
\setbeamercolor{background canvas}{bg=black!5}
\pgfpagesuselayout{4 on 1}[letterpaper,landscape,border shrink=2.5mm]
}
\newcommand{\return}[2]{\hyperlink{#1}{\beamerreturnbutton{#2}}}
\newcommand{\goto}[2]{\hyperlink{#1}{\beamergotobutton{#2}}}
\newcommand{\skipto}[2]{\hyperlink{#1}{\beamerskipbutton{#2}}}