diff --git a/debugging/lecture/debugging-chapter.tex b/debugging/lecture/debugging-chapter.tex
index 75472c9..caf8c35 100644
--- a/debugging/lecture/debugging-chapter.tex
+++ b/debugging/lecture/debugging-chapter.tex
@@ -1,4 +1,3 @@
-
 \documentclass[12pt]{book}
 
 \input{../../header}
diff --git a/header.tex b/header.tex
index 0369ca7..6511f0a 100644
--- a/header.tex
+++ b/header.tex
@@ -21,7 +21,7 @@
 \usepackage{pslatex}   % nice font for pdf file
 
 %%%% layout %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\usepackage[left=25mm,right=25mm,top=20mm,bottom=30mm]{geometry}
+\usepackage[a4paper,left=25mm,right=25mm,top=20mm,bottom=30mm]{geometry}
 \usepackage[within=chapter]{newfloat}
 \usepackage{tocloft}
 \setlength{\cftfigindent}{1.2em}
diff --git a/plotstyle.py b/plotstyle.py
index fe45614..511e282 100644
--- a/plotstyle.py
+++ b/plotstyle.py
@@ -1,7 +1,11 @@
 import matplotlib as mpl
 import matplotlib.pyplot as plt
 
-xkcd_style = False
+xkcd_style = True
+
+# default size of figure:
+figure_width = 15.0  # cm, should be set according to \textwidth in the latex document
+figure_height = 6.0  # cm, for a 1 x 2 figure
 
 # colors:
 colors = {
@@ -133,6 +137,13 @@ else:
     mpl.rcParams['xtick.major.size'] = 2.5
     mpl.rcParams['ytick.major.size'] = 2.5
     mpl.rcParams['legend.fontsize'] = 'x-small'
+mpl.rcParams['figure.figsize'] = cm_size(figure_width, figure_height)
+mpl.rcParams['figure.subplot.left'] = 0.11
+mpl.rcParams['figure.subplot.right'] = 0.99
+mpl.rcParams['figure.subplot.bottom'] = 0.23
+mpl.rcParams['figure.subplot.top'] = 0.96
+mpl.rcParams['figure.subplot.wspace'] = 0.4
+mpl.rcParams['figure.subplot.hspace'] = 0.2
 mpl.rcParams['figure.facecolor'] = 'white'
 #mpl.rcParams['axes.spines.left'] = True    # newer matplotlib only
 #mpl.rcParams['axes.spines.bottom'] = True
diff --git a/simulations/code/randomnumbers.m b/simulations/code/randomnumbers.m
index 22432b3..6fa3525 100644
--- a/simulations/code/randomnumbers.m
+++ b/simulations/code/randomnumbers.m
@@ -9,7 +9,7 @@ for k = 1:3
     rand(1, n)
 end
 
-% serial corraltion at lag 1:
+% serial correlation at lag 1:
 n = 10000;
 x = rand(n, 1);
 r1 = corr(x(1:end-1), x(2:end));
diff --git a/simulations/lecture/normaldata.py b/simulations/lecture/normaldata.py
index e3cc622..b79a960 100644
--- a/simulations/lecture/normaldata.py
+++ b/simulations/lecture/normaldata.py
@@ -15,9 +15,8 @@ if __name__ == "__main__":
     indices = np.arange(n)
     data = sigma*rng.randn(len(indices))+mu
 
-    fig = plt.figure(figsize=cm_size(16.0, 6.0))
-    spec = gridspec.GridSpec(nrows=1, ncols=2, width_ratios=[3, 1],
-                             left=0.12, bottom=0.23, right=0.97, top=0.96, wspace=0.08)
+    fig = plt.figure()
+    spec = gridspec.GridSpec(nrows=1, ncols=2, width_ratios=[3, 1], left=0.12, wspace=0.08)
     ax1 = fig.add_subplot(spec[0, 0])
     show_spines(ax1, 'lb')
     ax1.scatter(indices, data, c=colors['blue'], edgecolor='white', s=50)
diff --git a/simulations/lecture/randomnumbers.py b/simulations/lecture/randomnumbers.py
index 7a2609a..8795205 100644
--- a/simulations/lecture/randomnumbers.py
+++ b/simulations/lecture/randomnumbers.py
@@ -20,9 +20,9 @@ if __name__ == "__main__":
     lags = np.arange(-maxl, maxl+1, 1)
     corrs = [np.corrcoef(x[maxl:-maxl-1-l], x[maxl+l:-maxl-1])[0, 1] for l in lags]
 
-    fig = plt.figure(figsize=cm_size(16.0, 11.0))
+    fig = plt.figure(figsize=cm_size(figure_width, 1.8*figure_height))
     spec = gridspec.GridSpec(nrows=2, ncols=2,
-                             left=0.10, bottom=0.12, right=0.98, top=0.97,
+                             left=0.11, bottom=0.12, right=0.98, top=0.97,
                              wspace=0.4, hspace=0.6)
     
     ax = fig.add_subplot(spec[0, 0])
diff --git a/simulations/lecture/staticnonlinearity.py b/simulations/lecture/staticnonlinearity.py
index 737c723..627dc0d 100644
--- a/simulations/lecture/staticnonlinearity.py
+++ b/simulations/lecture/staticnonlinearity.py
@@ -20,9 +20,8 @@ if __name__ == "__main__":
     xx = np.linspace(xmin, xmax, 200)
     yy = boltzmann(xx, x0, k)
 
-    fig = plt.figure(figsize=cm_size(16.0, 6.0))
-    spec = gridspec.GridSpec(nrows=1, ncols=2,
-                             left=0.12, bottom=0.23, right=0.97, top=0.96, wspace=0.4)
+    fig = plt.figure()
+    spec = gridspec.GridSpec(nrows=1, ncols=2, left=0.1, wspace=0.4)
     ax1 = fig.add_subplot(spec[0, 0])
     show_spines(ax1, 'lb')
     ax1.plot(xx, yy, colors['red'], lw=2)