more tikz. write me an e-mail

src/tvalecturenotes.tex

@@ -36,8 +36,9 @@
 \centerline{licensed under GFDL.}
 \end{tiny}
 \vspace{4em}
-This version was created on \DTMnow.
-To get the latest version or to suggest some changes, please visit \href{https://gitlab.cs.fau.de/oz73ifuv/tv-a-lecture-notes}{https://gitlab.cs.fau.de/oz73ifuv/tv-a-lecture-notes}.
+This version was compiled on \DTMnow.
+To get the latest version or to suggest some changes, please visit \href{https://gitlab.cs.fau.de/oz73ifuv/tv-a-lecture-notes}{https://gitlab.cs.fau.de/oz73ifuv/tv-a-lecture-notes}, or write me an email at \href{mailto:stefan.kerman.gehr@fau.de}{stefan.kerman.gehr@fau.de}.
+In particular, it would be super nice if someone could create vector graphics for some of the figures.
 \newpage
 \tableofcontents
 

src/tvalecturenotes18.tex

@@ -131,8 +131,35 @@ So for example
 \paragraph{Pictorial representation} \(x_i\) as points, pairs / Feynman propagators as lines, partition as diagram.
 \begin{figure}
 	\Centering
-	\includegraphics[width=1\linewidth]{pictorialrepresentation.pdf}
-	\caption{Pictorial representation}
+	\(\bra{0} T(\phi(x_1) \phi(x_2) \phi(x_3) \phi(x_4))\ket{0}\)
+	=
+	\tikz[baseline=-0.2em]{
+		\draw (0,-0.5) -- (1,-0.5);
+		\draw (0,0.5) -- (1,0.5);
+		\draw [fill] (0,0.5) circle [radius=0.07] node [above] {1};
+		\draw [fill] (1,0.5) circle [radius=0.07] node [above] {2};
+		\draw [fill] (0,-0.5) circle [radius=0.07] node [below] {3};
+		\draw [fill] (1,-0.5) circle [radius=0.07] node [below] {4};
+	}
+	+
+	\tikz[baseline=-0.2em]{
+		\draw (0,-0.5) -- (1,0.5);
+		\draw (0,0.5) -- (1,-0.5);
+		\draw [fill] (0,0.5) circle [radius=0.07] node [above] {1};
+		\draw [fill] (1,0.5) circle [radius=0.07] node [above] {2};
+		\draw [fill] (0,-0.5) circle [radius=0.07] node [below] {3};
+		\draw [fill] (1,-0.5) circle [radius=0.07] node [below] {4};
+	}
+	+
+	\tikz[baseline=-0.2em]{
+		\draw (0,-0.5) -- (0,0.5);
+		\draw (1,0.5) -- (1,-0.5);
+		\draw [fill] (0,0.5) circle [radius=0.07] node [above] {1};
+		\draw [fill] (1,0.5) circle [radius=0.07] node [above] {2};
+		\draw [fill] (0,-0.5) circle [radius=0.07] node [below] {3};
+		\draw [fill] (1,-0.5) circle [radius=0.07] node [below] {4};
+	}
+	\caption{Pictorial Representation}
 	\label{fig:pictorialrepr}
 \end{figure}
 The diagram is in \autoref{fig:pictorialrepr}.