diff --git a/content/applying-automata-learning.tex b/content/applying-automata-learning.tex
index 3cb425d..cd280de 100644
--- a/content/applying-automata-learning.tex
+++ b/content/applying-automata-learning.tex
@@ -41,7 +41,29 @@ The most efficient such techniques use the set-up of \emph{active learning,} ill
 \startplacefigure
   [title={Active learning of reactive systems.},
    reference=fig:learning]
-\externalfigure[Learner.pdf][width=0.6\textwidth]
+\hbox{\starttikzpicture
+  [comp/.style={draw, minimum height=3.5cm, minimum width=2.25cm},
+   intcomp/.style={draw, inner sep=5pt},
+   conn/.style={at end, anchor=west, align=left, font=\tfx}]
+% https://tex.stackexchange.com/questions/103198/make-straight-line-between-two-nodes
+\node (l) [comp] {};
+\node [below] at (l.north) {Learner};
+
+\node (t) [comp, right=4.5cm of l] {};
+\node (t1) [below] at (t.north) {Teacher};
+
+\node (sut) [intcomp, below=.8cm of t.north] {SUT};
+\node (mbt) [intcomp, above=.8cm of t.south] {MBT tool};
+
+\draw[<-] ([yshift=2pt]sut.west) -- node[above=6pt, conn] {Membership Query} ([yshift=2pt]sut -| l.east);
+\draw[->] ([yshift=-2pt]sut.west) -- node[below=7pt, conn] {Output} ([yshift=-2pt]sut -| l.east);
+
+\draw[<-] ([yshift=2pt]mbt.west) -- node[above=6pt, conn] {Equivalence Query} ([yshift=2pt]mbt -| l.east);
+\draw[->] ([yshift=-2pt]mbt.west) -- node[below=7pt, conn] {\kw{yes} or \kw{no} with counterexample} ([yshift=-2pt]mbt -| l.east);
+
+\draw[->] ([xshift=2pt]sut.south) -- ([xshift=2pt]mbt.north);
+\draw[->] ([xshift=-2pt]mbt.north) -- ([xshift=-2pt]sut.south);
+\stoptikzpicture}
 \stopplacefigure
 
 The core of the teacher is a \emph{System Under Test} (SUT), a reactive system to which one can apply inputs and whose outputs one may observe.
@@ -118,7 +140,31 @@ Other products can be connected to an engine that pre- or postprocess the paper,
 \startplacefigure
   [title={Global overview of the engine software.},
    reference=fig:esra-overview]
-\externalfigure[ESRAOverview.pdf][width=0.5\textwidth]
+\hbox{\switchtobodyfont[small]\starttikzpicture
+  [comp/.style={draw, align=center, text width=2.2cm, fill=white, minimum height=13pt},
+   conn/.style={<->}]
+\forgetall
+\node (eia) [comp] {External Interface Adapters};
+\node (m) [comp, below=11pt of eia] {Managers};
+\node (f) [comp, below=11pt of m] {Functions};
+\node (os) [comp, fit=(eia) (m) (f), inner sep=0pt, xshift=3.5cm] {};
+\node at (os) (ost) [align=center, text width=2.2cm] {OS Facilities and Services};
+\node (c) [left=22pt of eia] {Controller};
+
+\draw
+  (eia) edge[conn] (m)
+  (m)   edge[conn] (f)
+  (eia) edge[conn] (os.west |- eia)
+  (m)   edge[conn] (os.west |- m)
+  (f)   edge[conn] (os.west |- f)
+  (eia) edge[conn] (c);
+  
+\startscope[on background layer]
+  \node (es) [rounded corners, fit=(eia) (m) (f) (os), inner sep=11pt, fill=black!10] {};
+  \node at (es.north) [rounded corners, fill=black!10] {Engine Software};
+\stopscope
+\stoptikzpicture}
+%\externalfigure[ESRAOverview.pdf][width=0.5\textwidth]
 \stopplacefigure
 
 \in{Figure}[fig:esra-overview] gives an overview of the software in a printer or copier.
@@ -151,7 +197,28 @@ Finally, it handles status transitions when an error occurs.
 \startplacefigure
   [title={Overview of the managers and clients connected to the ESM.},
    reference=fig:esm-protocols]
-\externalfigure[ESMProtocols.pdf][width=0.5\textwidth]
+\hbox{\switchtobodyfont[small]\starttikzpicture
+  [comp/.style={draw, align=center, text width=1.7cm, minimum width=1.8cm, minimum height=1.8cm, inner sep=0pt, fill=white},
+   coms/.style={comp, double copy shadow},
+   conn/.style={<->},
+   node distance=2.5cm]
+\forgetall
+\node (ehm) [comp]               {Error Handling Manager};
+\node (acm) [comp, right of=ehm] {Action Control Manager};
+\node (oc)  [coms, right of=acm] {Other Client};
+\node (tc)  [comp, below of=ehm] {Top Capsule};
+\node (esm) [comp, below of=acm, fill=black!10] {Engine Status Manager};
+\node (im)  [comp, below of=oc]  {Information Manager};
+\node (fn)  [coms, below of=esm] {Function};
+
+\path[conn]
+  (ehm) edge (esm)
+  (acm) edge (esm)
+  (oc)  edge (esm)
+  (tc)  edge (esm)
+  (im)  edge (esm)
+  (fn)  edge (esm);
+\stoptikzpicture}
 \stopplacefigure
 
 \in{Figure}[fig:esm-protocols] shows the different components to which the ESM is connected.
diff --git a/environment/tikz.tex b/environment/tikz.tex
index 9f0c5b8..6e997ca 100644
--- a/environment/tikz.tex
+++ b/environment/tikz.tex
@@ -1,12 +1,12 @@
 \startenvironment tikz
 
 \usemodule[tikz]
-\usetikzlibrary[automata, arrows, positioning, matrix, fit, decorations.pathreplacing]
+\usetikzlibrary[automata, arrows, positioning, matrix, fit, decorations.pathreplacing, shapes.geometric, shadows, backgrounds]
 
 \usemodule[pgfplots]
 
 % defaults
-\tikzset{node distance=2cm} % 'shorten >=2pt' only for automata
+\tikzset{node distance=2cm}
 \tikzset{/pgfplots/table/search path={data,../data}}
 \tikzset{initial text=, every initial by arrow/.style={shorten >=1pt}}