Make build system compatible with tikz externalization

.latexmkrc

@@ -1,4 +1,3 @@
 $pdflatex="pdflatex -shell-escape -interaction=nonstopmode -synctex=1 %O %S";
 $out_dir = 'build';
 $pdf_mode = 1;
-

Makefile

@@ -5,15 +5,15 @@ HANDOUTS := $(patsubst build/presentation_%.pdf,build/presentation_%_handout.pdf
 all: $(PRESENTATIONS) $(HANDOUTS)
 
 build/presentation_%.pdf: src/%/presentation.tex build/prepared
-	TEXINPUTS=./lib/cel-slides-template-2025:$$TEXINPUTS latexmk $<
+	TEXINPUTS=./lib/cel-slides-template-2025:$(dir $<):$$TEXINPUTS latexmk $<
 	mv build/presentation.pdf $@
 
 build/presentation_%_handout.pdf: src/%/presentation.tex build/prepared
-	TEXINPUTS=./lib/cel-slides-template-2025:$$TEXINPUTS latexmk -pdflatex='pdflatex %O "\def\ishandout{1}\input{%S}"' $<
+	TEXINPUTS=./lib/cel-slides-template-2025:$(dir $<):$$TEXINPUTS latexmk -pdflatex='pdflatex %O "\def\ishandout{1}\input{%S}"' $<
 	mv build/presentation.pdf $@
 
 build/prepared:
-	mkdir -p build
+	mkdir build
 	touch build/prepared
 
 .PHONY: clean

src/2026-01-16/presentation.tex

@@ -30,7 +30,7 @@
 \usepackage{tikz}
 \usepackage{tikz-3dplot}
 \usetikzlibrary{spy, external, intersections, positioning}
-%\tikzexternalize[prefix=build/]
+\tikzexternalize
 
 \usepackage{pgfplots}
 \pgfplotsset{compat=newest}
@@ -291,64 +291,6 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \subsection{Theorie Wiederholung}
 
-\begin{frame}
-    \frametitle{Unabhängigkeit \& Korrelation}
-
-    \vspace*{-10mm}
-
-    \begin{itemize}
-        \item Unabhängige ZV (stetig)
-            \begin{columns}
-                \column{\kitthreecolumns}
-                \begin{align*}
-                    X,Y \text{ unabhängig}
-                    \hspace{5mm} \Leftrightarrow \hspace{5mm}
-                    f_{X,Y}(x,y) = f_X(x)f_Y(y)
-                \end{align*}
-                \column{\kitthreecolumns}
-                \begin{lightgrayhighlightbox}
-                    Erinnerung: Unabhängige Ereignisse
-                    \begin{align*}
-                        X,Y \text{ \normalfont unabhängig}
-                        \hspace{5mm} \Leftrightarrow \hspace{5mm}
-                        P(AB) = P(A)P(B)
-                    \end{align*}
-                    \vspace*{-13mm}
-                \end{lightgrayhighlightbox}
-            \end{columns}
-            \pause
-        \item Kovarianz
-            \begin{columns}
-                \column{\kitthreecolumns}
-                \begin{align*}
-                    \text{cov}(X,Y) &= E\bigg( \big(X - E(X)\big) \big(Y
-                    - E(Y)\big) \bigg) \\
-                    &= E(XY) - E(X)E(Y)
-                \end{align*}
-                \column{\kitthreecolumns}
-                \begin{lightgrayhighlightbox}
-                    Erinnerung: Varianz
-                    \begin{align*}
-                        V(X) = E\big( \left(X - E(X)\right)^2 \big) = E(X^2) - E^2(X)
-                    \end{align*}
-                    \vspace*{-13mm}
-                \end{lightgrayhighlightbox}
-            \end{columns}
-        \item Korrelation
-            \begin{align*}
-                E(XY)
-            \end{align*}
-            \pause
-        \item Korrelationskoeffizient
-            \begin{align*}
-                \rho_{XY} = \frac{\text{cov}(X,Y)}{\sqrt{V(X)V(Y)}}
-                \hspace{25mm} \rho_{XY} = 0
-                \hspace{2mm}\Leftrightarrow\hspace{2mm}
-                E(XY) = E(X)E(Y)
-            \end{align*}
-    \end{itemize}
-\end{frame}
-
 \begin{frame}
     \frametitle{Mehrdimensionale Zufallsvariablen}
 
@@ -457,7 +399,65 @@
 \end{frame}
 
 \begin{frame}
-    \frametitle{Unabhängigkeit vs. Korrelation}
+    \frametitle{Unabhängigkeit \& Korrelation I}
+
+    \vspace*{-10mm}
+
+    \begin{itemize}
+        \item Unabhängige ZV (stetig)
+            \begin{columns}
+                \column{\kitthreecolumns}
+                \begin{align*}
+                    X,Y \text{ unabhängig}
+                    \hspace{5mm} \Leftrightarrow \hspace{5mm}
+                    f_{X,Y}(x,y) = f_X(x)f_Y(y)
+                \end{align*}
+                \column{\kitthreecolumns}
+                \begin{lightgrayhighlightbox}
+                    Erinnerung: Unabhängige Ereignisse
+                    \begin{align*}
+                        X,Y \text{ \normalfont unabhängig}
+                        \hspace{5mm} \Leftrightarrow \hspace{5mm}
+                        P(AB) = P(A)P(B)
+                    \end{align*}
+                    \vspace*{-13mm}
+                \end{lightgrayhighlightbox}
+            \end{columns}
+            \pause
+        \item Kovarianz
+            \begin{columns}
+                \column{\kitthreecolumns}
+                \begin{align*}
+                    \text{cov}(X,Y) &= E\bigg( \big(X - E(X)\big) \big(Y
+                    - E(Y)\big) \bigg) \\
+                    &= E(XY) - E(X)E(Y)
+                \end{align*}
+                \column{\kitthreecolumns}
+                \begin{lightgrayhighlightbox}
+                    Erinnerung: Varianz
+                    \begin{align*}
+                        V(X) = E\big( \left(X - E(X)\right)^2 \big) = E(X^2) - E^2(X)
+                    \end{align*}
+                    \vspace*{-13mm}
+                \end{lightgrayhighlightbox}
+            \end{columns}
+        \item Korrelation
+            \begin{align*}
+                E(XY)
+            \end{align*}
+            \pause
+        \item Korrelationskoeffizient
+            \begin{align*}
+                \rho_{XY} = \frac{\text{cov}(X,Y)}{\sqrt{V(X)V(Y)}}
+                \hspace{25mm} \rho_{XY} = 0
+                \hspace{2mm}\Leftrightarrow\hspace{2mm}
+                E(XY) = E(X)E(Y)
+            \end{align*}
+    \end{itemize}
+\end{frame}
+
+\begin{frame}
+    \frametitle{Unabhängigkeit \& Korrelation II}
 
     \vspace*{-15mm}