diff --git a/bootstrap/lecture/bootstrapsem.py b/bootstrap/lecture/bootstrapsem.py
index d8b0346..3a276bd 100644
--- a/bootstrap/lecture/bootstrapsem.py
+++ b/bootstrap/lecture/bootstrapsem.py
@@ -38,7 +38,7 @@ ax.annotate('sampling\ndistribution',
                 connectionstyle="angle3,angleA=20,angleB=120") )
 ax.annotate('bootstrap\ndistribution',
             xy=(0.13, 3.3), xycoords='data',
-            xytext=(0.25, 4), textcoords='data',
+            xytext=(0.22, 4), textcoords='data',
             arrowprops=dict(arrowstyle="->", relpos=(0.0,0.5),
                 connectionstyle="angle3,angleA=20,angleB=60") )
 ax.bar(bins[:-1]-0.25*db, hmusrs, 0.5*db, **fsB)
diff --git a/bootstrap/lecture/permutecorrelation.py b/bootstrap/lecture/permutecorrelation.py
index 2f10af8..c5f0db7 100644
--- a/bootstrap/lecture/permutecorrelation.py
+++ b/bootstrap/lecture/permutecorrelation.py
@@ -44,19 +44,19 @@ ax.annotate('Measured\ncorrelation\nis significant!',
                 connectionstyle="angle3,angleA=10,angleB=80") )
 ax.annotate('95% percentile',
             xy=(0.14, 0.9), xycoords='data',
-            xytext=(0.2, 4.0), textcoords='data', ha='left',
+            xytext=(0.18, 4.0), textcoords='data', ha='left',
             arrowprops=dict(arrowstyle="->", relpos=(0.1,0.0),
-                connectionstyle="angle3,angleA=30,angleB=70") )
+                connectionstyle="angle3,angleA=30,angleB=80") )
 ax.annotate('Distribution of\nuncorrelated\nsamples',
             xy=(-0.08, 3.6), xycoords='data',
             xytext=(-0.22, 5.0), textcoords='data', ha='left',
             arrowprops=dict(arrowstyle="->", relpos=(0.5,0.0),
-                connectionstyle="angle3,angleA=150,angleB=100") )
+                connectionstyle="angle3,angleA=150,angleB=110") )
 ax.bar(b[:-1], h, width=b[1]-b[0], **fsC)
 ax.bar(b[:-1][b[:-1]>=rq], h[b[:-1]>=rq], width=b[1]-b[0], **fsB)
 ax.plot( [rd, rd], [0, 1], **lsA)
 ax.set_xlim(-0.25, 0.35)
 ax.set_xlabel('Correlation coefficient')
-ax.set_ylabel('Probability density of H0')
+ax.set_ylabel('Prob. density of H0')
 
 plt.savefig('permutecorrelation.pdf')
diff --git a/likelihood/lecture/mlemean.py b/likelihood/lecture/mlemean.py
index 83b1bab..a1fb974 100644
--- a/likelihood/lecture/mlemean.py
+++ b/likelihood/lecture/mlemean.py
@@ -26,7 +26,7 @@ ax.set_ylim(-0.02, 0.85)
 ax.set_xticks(np.arange(0, 5))
 ax.set_yticks(np.arange(0, 0.9, 0.2))
 ax.set_xlabel('x')
-ax.set_ylabel('Probability density')
+ax.set_ylabel('Prob. density')
 s = 1
 for mu in mus :
     r = 5.0*rng.rand()+2.0
@@ -35,11 +35,11 @@ for mu in mus :
     ax.annotate('', xy=(mu, 0.02), xycoords='data',
                 xytext=(mu, 0.75), textcoords='data',
                 arrowprops=dict(arrowstyle="->", relpos=(0.5,0.5),
-                connectionstyle=cs), zorder=1)
+                connectionstyle=cs), zorder=10)
     if mu > rmu :
-        ax.text(mu-0.1, 0.04, '?', zorder=1, ha='right')
+        ax.text(mu-0.1, 0.04, '?', zorder=10, ha='right')
     else :
-        ax.text(mu+0.1, 0.04, '?', zorder=1)
+        ax.text(mu+0.1, 0.04, '?', zorder=10)
 for k, ls in enumerate([lsCm, lsBm, lsDm]) :
     ax.plot(x, g[:,k], zorder=5, **ls)
 ax.plot(xd, 0.05*rng.rand(len(xd))+0.2, zorder=10, **psAm)
diff --git a/likelihood/lecture/mlepdf.py b/likelihood/lecture/mlepdf.py
index ddbcb57..3b1a851 100644
--- a/likelihood/lecture/mlepdf.py
+++ b/likelihood/lecture/mlepdf.py
@@ -29,7 +29,7 @@ ax1.set_ylim(0.0, 0.42)
 ax1.set_xticks(np.arange(0, 11, 2))
 ax1.set_yticks(np.arange(0, 0.42, 0.1))
 ax1.set_xlabel('x')
-ax1.set_ylabel('Probability density')
+ax1.set_ylabel('Prob. density')
 ax1.plot(xx, yy, label='pdf', **lsB)
 ax1.plot(xx, yf, label='mle', **lsCm)
 kernel = st.gaussian_kde(xd)
@@ -54,7 +54,7 @@ ax2.set_xticks(np.arange(0, 11, 2))
 ax2.set_xlabel('x')
 ax2.set_ylim(0.0, 0.42)
 ax2.set_yticks(np.arange(0, 0.42, 0.1))
-ax2.set_ylabel('Probability density')
+ax2.set_ylabel('Prob. density')
 ax2.plot(xx, yy, label='pdf', **lsB)
 ax2.plot(xx, yc, label='fit', **lsCm)
 ax2.bar(b[:-1], h, np.diff(b), **fsA)
diff --git a/likelihood/lecture/mlepropline.py b/likelihood/lecture/mlepropline.py
index 906a3f2..cecd350 100644
--- a/likelihood/lecture/mlepropline.py
+++ b/likelihood/lecture/mlepropline.py
@@ -6,7 +6,7 @@ from plotstyle import *
 
 fig = plt.figure()
 spec = gridspec.GridSpec(nrows=1, ncols=2, wspace=0.3,
-                         **adjust_fs(fig, left=5.5))
+                         **adjust_fs(fig, left=5.5, top=1))
 spec1 = gridspec.GridSpecFromSubplotSpec(1, 2, spec[0, 0], width_ratios=[3, 1], wspace=0.0)
 spec2 = gridspec.GridSpecFromSubplotSpec(1, 2, spec[0, 1], width_ratios=[3, 1], wspace=0.0)
 
@@ -34,7 +34,7 @@ ax.set_ylabel('y')
 ax.plot(x, y, label='data', zorder=10, **psAm)
 ax.plot(xx, yy, label='original', zorder=5, **lsB)
 ax.plot(xx, yf, label='fit', zorder=7, **lsCm)
-ax.legend(loc='upper left', bbox_to_anchor=(0.0, 1.15))
+ax.legend(loc='upper left', bbox_to_anchor=(-0.05, 1.2))
 
 ax = fig.add_subplot(spec1[0, 1])
 ax.show_spines('l')
diff --git a/plotstyle.py b/plotstyle.py
index 729962d..7e3ba8c 100644
--- a/plotstyle.py
+++ b/plotstyle.py
@@ -277,7 +277,7 @@ def axis_label(label, unit=None):
     if not unit:
         return label
     elif xkcd_style:
-        return '%s / %s' % (label, unit)
+        return '%s/%s' % (label, unit)
     else:
         return '%s [%s]' % (label, unit)
 
diff --git a/pointprocesses/lecture/firingrates.py b/pointprocesses/lecture/firingrates.py
index b7029fa..087e7ee 100644
--- a/pointprocesses/lecture/firingrates.py
+++ b/pointprocesses/lecture/firingrates.py
@@ -149,7 +149,7 @@ def plot_comparison(spike_times, bin_width, sigma, max_t=30., dt=1e-4):
     ax1.show_spines('b')
     ax1.vlines(times[times < (100000*dt)], ymin=0, ymax=1, color=colors['blue'], lw=1.5)
     #ax1.set_ylabel('Spikes')
-    ax1.text(-0.105, 0.5, 'Spikes', transform=ax1.transAxes,
+    ax1.text(-0.13, 0.5, 'Spikes', transform=ax1.transAxes,
              rotation='vertical', va='center')
     ax1.set_xlim(2.5, 3.5)
     ax1.set_ylim(-0.2, 1)
@@ -159,7 +159,7 @@ def plot_comparison(spike_times, bin_width, sigma, max_t=30., dt=1e-4):
     ax2.plot(time, inst_rate, color=colors['orange'], lw=2)
     ax2.text(1.0, 1.0, 'instantaneous rate', transform=ax2.transAxes, ha='right')
     #ax2.set_ylabel('Rate', 'Hz')
-    ax2.text(-0.105, 0.5, axis_label('Rate', 'Hz'), transform=ax2.transAxes,
+    ax2.text(-0.13, 0.5, axis_label('Rate', 'Hz'), transform=ax2.transAxes,
              rotation='vertical', va='center')
     ax2.set_xlim(2.5, 3.5)
     ax2.set_ylim(0, 300)
@@ -170,7 +170,7 @@ def plot_comparison(spike_times, bin_width, sigma, max_t=30., dt=1e-4):
     ax3.plot(time, binn_rate, color=colors['orange'], lw=2)
     ax3.text(1.0, 1.0, 'binned rate', transform=ax3.transAxes, ha='right')
     #ax3.set_ylabel('Rate', 'Hz')
-    ax3.text(-0.105, 0.5, axis_label('Rate', 'Hz'), transform=ax3.transAxes,
+    ax3.text(-0.13, 0.5, axis_label('Rate', 'Hz'), transform=ax3.transAxes,
              rotation='vertical', va='center')
     ax3.set_xlim(2.5, 3.5)
     ax3.set_ylim(0, 300)
@@ -182,7 +182,7 @@ def plot_comparison(spike_times, bin_width, sigma, max_t=30., dt=1e-4):
     ax4.text(1.0, 1.0, 'convolved rate', transform=ax4.transAxes, ha='right')
     ax4.set_xlabel('Time', 's')
     #ax4.set_ylabel('Rate', 'Hz')
-    ax4.text(-0.105, 0.5, axis_label('Rate', 'Hz'), transform=ax4.transAxes,
+    ax4.text(-0.13, 0.5, axis_label('Rate', 'Hz'), transform=ax4.transAxes,
              rotation='vertical', va='center')
     ax4.set_xlim(2.5, 3.5)
     ax4.set_xticks([2.5, 2.75, 3.0, 3.25, 3.5])
diff --git a/pointprocesses/lecture/isimethod.py b/pointprocesses/lecture/isimethod.py
index 750b840..ef28b8f 100644
--- a/pointprocesses/lecture/isimethod.py
+++ b/pointprocesses/lecture/isimethod.py
@@ -31,7 +31,7 @@ def setup_axis(spikes_ax, rate_ax):
     spikes_ax.show_spines('')
     spikes_ax.set_yticks([])
     spikes_ax.set_ylim(-0.2, 1.0)
-    spikes_ax.text(-0.1, 0.5, 'Spikes', transform=spikes_ax.transAxes, rotation='vertical', va='center')
+    spikes_ax.text(-0.11, 0.5, 'Spikes', transform=spikes_ax.transAxes, rotation='vertical', va='center')
     spikes_ax.set_xlim(-1, 500)
     spikes_ax.set_xticklabels([])
     #spikes_ax.set_xticklabels(np.arange(0., 600, 100))
@@ -39,7 +39,7 @@ def setup_axis(spikes_ax, rate_ax):
     spikes_ax.show_spines('lb')
     rate_ax.set_xlabel('Time', 'ms')
     #rate_ax.set_ylabel('Firing rate', 'Hz')
-    rate_ax.text(-0.1, 0.5, axis_label('Rate', 'Hz'), transform=rate_ax.transAxes,
+    rate_ax.text(-0.11, 0.5, axis_label('Rate', 'Hz'), transform=rate_ax.transAxes,
                  rotation='vertical', va='center')
     rate_ax.set_xlim(0, 500)
     #rate_ax.set_xticklabels(np.arange(0., 600, 100))
@@ -126,7 +126,7 @@ def plot_isi_method():
         t_start = 1000*spike_times[i-1]
         t = 1000*spike_times[i]
         spikes_ax.plot([t_start, t_start], [0., 1.], color=colors['blue'], lw=2)
-        spikes_ax.annotate(s='', xy=(t_start, 0.5), xytext=(t,0.5), arrowprops=dict(arrowstyle='<->'), color=colors['red'])
+        spikes_ax.annotate('', xy=(t_start, 0.5), xytext=(t,0.5), arrowprops=dict(arrowstyle='<->'), color=colors['red'])
         spikes_ax.text(0.5*(t_start+t), 1.05, 
                     "{0:.0f}".format((t - t_start)),
                     color=colors['red'], ha='center')
diff --git a/pointprocesses/lecture/pointprocessscetchA.eps b/pointprocesses/lecture/pointprocessscetchA.eps
index 2c18dd1..2383569 100644
--- a/pointprocesses/lecture/pointprocessscetchA.eps
+++ b/pointprocesses/lecture/pointprocessscetchA.eps
@@ -1,7 +1,7 @@
 %!PS-Adobe-2.0 EPSF-2.0
 %%Title: pointprocessscetchA.tex
-%%Creator: gnuplot 5.0 patchlevel 5
-%%CreationDate: Tue Jan  7 10:05:37 2020
+%%Creator: gnuplot 4.6 patchlevel 4
+%%CreationDate: Tue Oct 27 23:58:04 2020
 %%DocumentFonts: 
 %%BoundingBox: 50 50 373 135
 %%EndComments
@@ -18,7 +18,6 @@ gnudict begin
 /Dashlength 1 def
 /Landscape false def
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 /Rounded true def
 /ClipToBoundingBox false def
 /SuppressPDFMark false def
@@ -30,11 +29,11 @@ gnudict begin
 %
 /vshift -73 def
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-  10.0 Dashlength userlinewidth gnulinewidth div mul mul mul
+  10.0 Dashlength mul mul
   Rounded { currentlinewidth 0.75 mul sub dup 0 le { pop 0.01 } if } if
 } def
 /dl2 {
-  10.0 Dashlength userlinewidth gnulinewidth div mul mul mul
+  10.0 Dashlength mul mul
   Rounded { currentlinewidth 0.75 mul add } if
 } def
 /hpt_ 31.5 def
@@ -48,7 +47,7 @@ gnudict begin
   } if
 } def
 %
-% Gnuplot Prolog Version 5.1 (Oct 2015)
+% Gnuplot Prolog Version 4.6 (September 2012)
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 %/SuppressPDFMark true def
 %
@@ -65,11 +64,11 @@ gnudict begin
 /vpt2 vpt 2 mul def
 /hpt2 hpt 2 mul def
 /Lshow {currentpoint stroke M 0 vshift R 
-	Blacktext {gsave 0 setgray textshow grestore} {textshow} ifelse} def
+	Blacktext {gsave 0 setgray show grestore} {show} ifelse} def
 /Rshow {currentpoint stroke M dup stringwidth pop neg vshift R
-	Blacktext {gsave 0 setgray textshow grestore} {textshow} ifelse} def
+	Blacktext {gsave 0 setgray show grestore} {show} ifelse} def
 /Cshow {currentpoint stroke M dup stringwidth pop -2 div vshift R 
-	Blacktext {gsave 0 setgray textshow grestore} {textshow} ifelse} def
+	Blacktext {gsave 0 setgray show grestore} {show} ifelse} def
 /UP {dup vpt_ mul /vpt exch def hpt_ mul /hpt exch def
   /hpt2 hpt 2 mul def /vpt2 vpt 2 mul def} def
 /DL {Color {setrgbcolor Solid {pop []} if 0 setdash}
@@ -83,7 +82,7 @@ gnudict begin
 /PL {stroke userlinewidth setlinewidth
 	Rounded {1 setlinejoin 1 setlinecap} if} def
 3.8 setmiterlimit
-% Classic Line colors (version 5.0)
+% Default Line colors
 /LCw {1 1 1} def
 /LCb {0 0 0} def
 /LCa {0 0 0} def
@@ -96,21 +95,19 @@ gnudict begin
 /LC6 {0 0 0} def
 /LC7 {1 0.3 0} def
 /LC8 {0.5 0.5 0.5} def
-% Default dash patterns (version 5.0)
-/LTB {BL [] LCb DL} def
+% Default Line Types
 /LTw {PL [] 1 setgray} def
-/LTb {PL [] LCb DL} def
+/LTb {BL [] LCb DL} def
 /LTa {AL [1 udl mul 2 udl mul] 0 setdash LCa setrgbcolor} def
 /LT0 {PL [] LC0 DL} def
-/LT1 {PL [2 dl1 3 dl2] LC1 DL} def
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-/LT8 {PL [2 dl1 2 dl2 2 dl1 6 dl2] LC8 DL} def
-/SL {[] 0 setdash} def
+/LT1 {PL [4 dl1 2 dl2] LC1 DL} def
+/LT2 {PL [2 dl1 3 dl2] LC2 DL} def
+/LT3 {PL [1 dl1 1.5 dl2] LC3 DL} def
+/LT4 {PL [6 dl1 2 dl2 1 dl1 2 dl2] LC4 DL} def
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+/LT7 {PL [1 dl1 2 dl2 6 dl1 2 dl2 1 dl1 2 dl2] LC7 DL} def
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 /Pnt {stroke [] 0 setdash gsave 1 setlinecap M 0 0 V stroke grestore} def
 /Dia {stroke [] 0 setdash 2 copy vpt add M
   hpt neg vpt neg V hpt vpt neg V
@@ -332,14 +329,9 @@ gnudict begin
 %
 /languagelevel where
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-dup 2 lt
-	{/InterpretLevel1 true def
-	 /InterpretLevel3 false def}
-	{/InterpretLevel1 Level1 def
-	 2 gt
-	    {/InterpretLevel3 Level3 def}
-	    {/InterpretLevel3 false def}
-	 ifelse }
+ 2 lt
+	{/InterpretLevel1 true def}
+	{/InterpretLevel1 Level1 def}
  ifelse
 %
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@@ -428,7 +420,6 @@ Level1 {Level1PatternFill} {Level2PatternFill} ifelse
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 dup length dict begin {1 index /FID eq {pop pop} {def} ifelse} forall
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-%
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 /SDict 10 dict def
@@ -438,42 +429,14 @@ systemdict /pdfmark known not {
 SDict begin [
   /Title (pointprocessscetchA.tex)
   /Subject (gnuplot plot)
-  /Creator (gnuplot 5.0 patchlevel 5)
-  /Author (benda)
+  /Creator (gnuplot 4.6 patchlevel 4)
+  /Author (jan)
 %  /Producer (gnuplot)
 %  /Keywords ()
-  /CreationDate (Tue Jan  7 10:05:37 2020)
+  /CreationDate (Tue Oct 27 23:58:04 2020)
   /DOCINFO pdfmark
 end
 } ifelse
-%
-% Support for boxed text - Ethan A Merritt May 2005
-%
-/InitTextBox { userdict /TBy2 3 -1 roll put userdict /TBx2 3 -1 roll put
-           userdict /TBy1 3 -1 roll put userdict /TBx1 3 -1 roll put
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-/ExtendTextBox { Boxing
-    { gsave dup false charpath pathbbox
-      dup TBy2 gt {userdict /TBy2 3 -1 roll put} {pop} ifelse
-      dup TBx2 gt {userdict /TBx2 3 -1 roll put} {pop} ifelse
-      dup TBy1 lt {userdict /TBy1 3 -1 roll put} {pop} ifelse
-      dup TBx1 lt {userdict /TBx1 3 -1 roll put} {pop} ifelse
-      grestore } if } def
-/PopTextBox { newpath TBx1 TBxmargin sub TBy1 TBymargin sub M
-               TBx1 TBxmargin sub TBy2 TBymargin add L
-	       TBx2 TBxmargin add TBy2 TBymargin add L
-	       TBx2 TBxmargin add TBy1 TBymargin sub L closepath } def
-/DrawTextBox { PopTextBox stroke /Boxing false def} def
-/FillTextBox { gsave PopTextBox 1 1 1 setrgbcolor fill grestore /Boxing false def} def
-0 0 0 0 InitTextBox
-/TBxmargin 20 def
-/TBymargin 20 def
-/Boxing false def
-/textshow { ExtendTextBox Gshow } def
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@@ -487,9 +450,10 @@ newpath
 2.000 UL
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+LTb
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 stroke
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@@ -526,16 +488,11 @@ LCb setrgbcolor
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diff --git a/pointprocesses/lecture/pointprocessscetchA.pdf b/pointprocesses/lecture/pointprocessscetchA.pdf
index 0d2f26e..59b0583 100644
Binary files a/pointprocesses/lecture/pointprocessscetchA.pdf and b/pointprocesses/lecture/pointprocessscetchA.pdf differ
diff --git a/pointprocesses/lecture/pointprocessscetchB.eps b/pointprocesses/lecture/pointprocessscetchB.eps
index 83c9cea..d55c96f 100644
--- a/pointprocesses/lecture/pointprocessscetchB.eps
+++ b/pointprocesses/lecture/pointprocessscetchB.eps
@@ -1,7 +1,7 @@
 %!PS-Adobe-2.0 EPSF-2.0
 %%Title: pointprocessscetchB.tex
-%%Creator: gnuplot 5.0 patchlevel 5
-%%CreationDate: Tue Jan  7 10:05:38 2020
+%%Creator: gnuplot 4.6 patchlevel 4
+%%CreationDate: Tue Oct 27 23:58:04 2020
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@@ -18,7 +18,6 @@ gnudict begin
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@@ -30,11 +29,11 @@ gnudict begin
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+  10.0 Dashlength mul mul
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 /hpt_ 31.5 def
@@ -48,7 +47,7 @@ gnudict begin
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 /hpt2 hpt 2 mul def
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-	Blacktext {gsave 0 setgray textshow grestore} {textshow} ifelse} def
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-	Blacktext {gsave 0 setgray textshow grestore} {textshow} ifelse} def
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 /PL {stroke userlinewidth setlinewidth
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-% Classic Line colors (version 5.0)
+% Default Line colors
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-% Default dash patterns (version 5.0)
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diff --git a/pointprocesses/lecture/pointprocessscetchB.pdf b/pointprocesses/lecture/pointprocessscetchB.pdf
index c9d4fdc..2055658 100644
Binary files a/pointprocesses/lecture/pointprocessscetchB.pdf and b/pointprocesses/lecture/pointprocessscetchB.pdf differ
diff --git a/regression/lecture/gradient.py b/regression/lecture/gradient.py
index a191eeb..ec4b53f 100644
--- a/regression/lecture/gradient.py
+++ b/regression/lecture/gradient.py
@@ -24,7 +24,7 @@ ax.set_xlabel('x')
 ax.set_ylabel('y', rotation='horizontal')
 ax.set_xticks(np.arange(x1, x2+0.1, 1.0))
 ax.set_yticks(np.arange(x1, x2+0.1, 1.0))
-ax.contour(X, Y, Z, linewidths=2, zorder=0)
+ax.contour(X, Y, Z, linewidths=2, cmap='jet', zorder=0)
 
 # gradients:
 xxg = [-1.1, 1.4, -1.0]
@@ -35,8 +35,8 @@ for xg, yg in zip(xxg, yyg) :
     ax.scatter(xg, yg, c='k', s=100, zorder=10)
     ax.quiver([xg, xg], [yg, yg], [g[0], 0.0], [0.0, g[1]], units='xy', angles='uv', scale_units='x', scale=0.5, zorder=10)
     ax.quiver([xg], [yg], [g[0]], [g[1]], units='xy', angles='uv', scale_units='x', scale=0.5, zorder=10, lw=2)
-ax.text(-0.8, -1.5, '$\partial f/\partial x$', ha='center', zorder=20)
-ax.text(-1.55, -0.8, '$\partial f/\partial y$', va='center', rotation='vertical', zorder=20)
-ax.text(-0.4, -0.8, r'$\nabla f$', ha='left', zorder=20)
+ax.text(-0.8, -1.4, '$\partial f/\partial x$', ha='center', zorder=20)
+ax.text(-1.45, -0.8, '$\partial f/\partial y$', va='center', rotation='vertical', zorder=20)
+ax.text(-0.5, -0.8, r'$\nabla f$', ha='left', zorder=20)
 
 plt.savefig('gradient.pdf')