ADDED   Makefile
Index: Makefile
==================================================================
--- Makefile
+++ Makefile
@@ -0,0 +1,27 @@
+PNGS = pngs/network-private.png pngs/network-public.png pngs/network-community.png
+PNGS_BEAMER = pngs/confine,background.png
+
+.PHONY:	clean
+
+all:	slides,lightning.pdf
+
+slides,lightning.pdf:	script,lightning.txt $(PNGS) slides-header.tex $(PNGS_BEAMER)
+	pandoc -t beamer -H slides-header.tex slides,lightning.txt -o $@
+
+slides,lightning.html:	script,lightning.txt $(PNGS)
+	pandoc -t dzslides --self-contained script,lightning.txt -o $@
+
+pngs/confine,background.png:	logos/confine,logo.svg
+	inkscape -z -D -e $@ -w 1024 $<
+
+pngs/network-private.png:	diagrams/network-private.dia
+	dia -e $@ -s 1024x $<
+
+pngs/network-public.png:	diagrams/network-public.dia
+	dia -e $@ -s 1024x $<
+
+pngs/network-community.png:	diagrams/network-community.dia
+	dia -e $@ -s 1024x $<
+
+clean:
+	rm -f $(PNGS) $(PNGS_BEAMER) slides,lightning.pdf slides,lightning.html

ADDED   slides-header.tex
Index: slides-header.tex
==================================================================
--- slides-header.tex
+++ slides-header.tex
@@ -0,0 +1,16 @@
+%% https://tex.stackexchange.com/questions/26458/beamer-background-image-centered
+%% https://tex.stackexchange.com/questions/74038/transparent-image-background-in-beamer
+\usepackage{tikz}
+\usebackgroundtemplate {
+  \vbox to \paperheight {
+    \vfil
+    \hbox to \paperwidth {
+      \hfil
+      \tikz\node[opacity=0.25] {
+        \includegraphics[width=0.75\textwidth]{pngs/confine,background.png}
+      };
+      \hfil
+    }
+    \vfil
+  }
+}