--- a/mercurial.tex
+++ b/mercurial.tex
@@ -1,6 +1,17 @@
 \documentclass[t,noamsthm]{beamer}
 
 \usepackage{tikz}
+\usetikzlibrary{chains,positioning,shapes}
+\tikzstyle{every picture}=[thick]
+\tikzstyle{rev}=[minimum size=3mm, draw=red!50!black!50, top
+  color=white, bottom color = red!50!black!20]
+\tikzstyle{repository}=[cylinder,shape border rotate=90, draw=structure,
+  shade, left color=structure!50, right color=structure!50,
+  middle color=structure!10, aspect=0.15, minimum height=20mm,
+  text width=20mm, text centered]
+\tikzstyle{working copy}=[text width=15mm, inner sep=3mm,
+  draw=yellow!40!red, fill=yellow!20!white]
+\tikzstyle{every join}=[->]
 
 \mode<presentation>{
   \setbeamertemplate{navigation symbols}{}