diff --git a/report.tex b/report.tex
index cb319b1..5436dcd 100644
--- a/report.tex
+++ b/report.tex
@@ -282,7 +282,7 @@
 
       % \node[draw=none, above=1mm of gh, font=\scriptsize] {full first order};
       \end{tikzpicture}
-      \caption{Blue: second order systems; Red: first order systems. Solid arrows: direct modifications; Dashed arrows: indirect relation. Bidirectional arrows: equivalence.}
+      \caption{Commenly used systems.\footnote{Blue: second order systems; Red: first order systems. Solid arrows: direct modifications; Dashed arrows: indirect relation. Bidirectional arrows: equivalence.}}
     \end{figure}
     \begin{itemize}
       \item Z4 and GH evolve the physical metric, and thus not compatible with the moving puncture method.
@@ -294,6 +294,10 @@
     \end{itemize}
   \end{frame}
 
+  \begin{frame}{Searching for a first order Z4c}{Why Z4c?}
+    
+  \end{frame}
+
   \begin{frame}{Searching for a first order Z4c}{Hyperbolicity of first order systems}
     \subsection{Hyperbolicity of first order systems}
     Say we have a list of variables $u^I$, and a first order PDE system