diff --git a/report.tex b/report.tex
index 3ac6f51..f97edfb 100644
--- a/report.tex
+++ b/report.tex
@@ -240,90 +240,42 @@
   \begin{frame}{Searching for a first order Z4c}{Why Z4c?}
     \section{Searching for a first order Z4c}
     \subsection{Why Z4c?}
-    \begin{tikzpicture}[scale=0.5,
-  font=\small,
+    \begin{tikzpicture}[
   >=Latex,
-  node distance=12mm and 14mm,
+  node distance=8mm and 10mm,
+  every node/.style={font=\small},
   sys/.style={
     draw,
     rounded corners,
     align=center,
-    minimum width=22mm,
-    minimum height=9mm,
-    inner sep=3pt
+    minimum width=15mm,
+    minimum height=7mm,
+    inner sep=2pt
   },
-  second/.style={sys, fill=blue!6},
-  first/.style={sys, fill=red!7, very thick},
-  note/.style={align=center, font=\footnotesize},
-  solidarrow/.style={->, thick},
-  dashedarrow/.style={->, thick, dashed},
-  influence/.style={->, semithick, dotted}
+  std/.style={sys, fill=blue!8},
+  fo/.style={sys, fill=red!10, very thick},
+  rel/.style={->, thick},
+  weak/.style={->, semithick, dashed}
 ]
 
-% -------------------------------------------------
-% upper row: non-fully-first-order / standard forms
-% -------------------------------------------------
-\node[second] (bssn) {BSSN};
-\node[second, right=28mm of bssn] (z4) {Z4};
-\node[second, right=22mm of z4] (z4c) {Z4c};
-\node[second, right=22mm of z4c] (ccz4) {CCZ4};
+\node[std] (bssn) {BSSN};
+\node[std, right=of bssn] (z4) {Z4};
+\node[std, right=of z4] (z4c) {Z4c};
+\node[std, right=of z4c] (ccz4) {CCZ4};
 
-% lower row: fully first-order systems
-\node[first, below=22mm of bssn] (fobssn) {FOBSSN};
-\node[first, below=22mm of ccz4] (foccz4) {FOCCZ4};
-\node[first, below=22mm of z4c] (gh) {GH\\(usually first-order)};
+\node[fo, below=10mm of bssn] (fobssn) {FOBSSN};
+\node[fo, below=10mm of z4c] (gh) {GH};
+\node[fo, below=10mm of ccz4] (foccz4) {FOCCZ4};
 
-% group boxes
-\node[
-  draw,
-  rounded corners,
-  inner sep=6pt,
-  fit=(bssn)(z4)(z4c)(ccz4),
-  label={[font=\footnotesize]above:second-order-in-space / standard formulations}
-] (upperbox) {};
+\draw[rel] (z4) -- (z4c);
+\draw[rel] (z4) to[bend left=18] (ccz4);
+\draw[weak] (bssn) -- (z4c);
 
-\node[
-  draw=red!70!black,
-  rounded corners,
-  very thick,
-  inner sep=6pt,
-  fit=(fobssn)(foccz4)(gh),
-  label={[font=\footnotesize]above:{\textbf{fully first-order systems}}}
-] (lowerbox) {};
-
-% -------------------------------------------------
-% arrows among upper systems
-% -------------------------------------------------
-\draw[solidarrow] (z4) -- node[above, note] {conformal\\reformulation} (z4c);
-\draw[solidarrow] (z4) to[bend left=18] node[above, note] {conformal + covariant\\constraint damping} (ccz4);
-
-% BSSN <-> Z4c relation: not a clean parent/child, so use dotted influence
-\draw[influence] (bssn) -- node[above, note] {BSSN-like\\variables} (z4c);
-
-% -------------------------------------------------
-% arrows to first-order systems
-% -------------------------------------------------
-\draw[solidarrow] (bssn) -- node[left, note] {first-order\\reduction} (fobssn);
-\draw[solidarrow] (ccz4) -- node[right, note] {first-order\\reduction} (foccz4);
-
-% GH relation: keep it cautious
-\draw[dashedarrow] (z4) -- node[right, note] {closely related\\(principal-part / variable-choice sense)} (gh);
-
-% optional weak relation from Z4c to FOCCZ4
-\draw[influence] (z4c.south east) to[bend left=18]
-  node[right, note] {same Z4-family} (foccz4.north west);
-
-% -------------------------------------------------
-% tiny legend
-% -------------------------------------------------
-\node[note, below=8mm of gh] (legend) {%
-\begin{tabular}{@{}c l@{}}
-\raisebox{0.2ex}{\tikz{\draw[->,thick] (0,0)--(0.7,0);}} & fairly direct reformulation / reduction \\
-\raisebox{0.2ex}{\tikz{\draw[->,thick,dashed] (0,0)--(0.7,0);}} & close relation, but not drawn as a strict descendant \\
-\raisebox{0.2ex}{\tikz{\draw[->,semithick,dotted] (0,0)--(0.7,0);}} & shared variables / family resemblance / influence
-\end{tabular}
-};
+\draw[rel] (bssn) -- (fobssn);
+\draw[rel] (ccz4) -- (foccz4);
+\draw[weak] (z4) -- (gh);
 
+\node[draw=none, above=1mm of gh, font=\scriptsize] {full first order};
 \end{tikzpicture}
   \end{frame}