diff --git a/IV/Makefile b/IV/Makefile
index 8670cf8..b521c58 100644
--- a/IV/Makefile
+++ b/IV/Makefile
@@ -21,6 +21,7 @@ FIGURES = test-figures \
 					selfcrossing-1-before \
 					selfcrossing-1-after
 
+# paper sizes in mm
 A4p = 210x297
 A4l = 297x210
 A5p = 148x210
@@ -31,6 +32,10 @@ A7p = 74x105
 A7l = 105x74
 A8p = 52x74
 A8l = 74x52
+# interesting scales:
+# - 1:10000 (GDR10)
+# - 1:50000 (GDR50)
+# - 1:250000 (GDR250)
 
 #################################
 # The thesis, publishable version
diff --git a/IV/layer2img.py b/IV/layer2img.py
index 7b62ec5..ecb5df7 100644
--- a/IV/layer2img.py
+++ b/IV/layer2img.py
@@ -10,7 +10,7 @@ from matplotlib import rc
 CMAP = 'tab20c'
 
 BOUNDS = ('xmin', 'ymin', 'xmax', 'ymax')
-INCH_MM = 25.4  # mm
+INCH_MM = 25.4
 BLACK, GREEN, ORANGE, PURPLE = '#000000', '#1b9e77', '#d95f02', '#7570b3'
 PSQL_CREDS = "host=127.0.0.1 dbname=osm user=osm password=osm"
 
diff --git a/IV/mj-msc.tex b/IV/mj-msc.tex
index 0324902..db669a7 100644
--- a/IV/mj-msc.tex
+++ b/IV/mj-msc.tex
@@ -85,7 +85,7 @@ Current open-source line generalization solutions have their roots in
 NOTICE: this value should be copied to layer2img.py:TEXTWIDTH, so dimensions
 of inline images are reasonable.
 
-Text width in cm: {\printinunitsof{cm}\prntlen{\textwidth}}
+textwidth in cm: {\printinunitsof{cm}\prntlen{\textwidth}}
 \fi
 
 When creating small-scale maps, often the detail of the data source is greater
@@ -278,7 +278,7 @@ direction.
 
 \begin{figure}[h]
     \centering
-    \includegraphics[width=\linewidth]{test-figures}
+    \includegraphics[width=\textwidth]{test-figures}
     \caption{Line geometries for automated test cases}
     \label{fig:test-figures}
 \end{figure}
@@ -340,7 +340,7 @@ but with bends colored as polygons: each color is a distinctive bend.
 
 \begin{figure}[h]
     \centering
-    \includegraphics[width=\linewidth]{fig8-definition-of-a-bend}
+    \includegraphics[width=\textwidth]{fig8-definition-of-a-bend}
     \caption{Originally Figure 8: detected bends are highlighted}
     \label{fig:fig8-definition-of-a-bend}
 \end{figure}
diff --git a/IV/tests.sql b/IV/tests.sql
index 521e135..a8cef4e 100644
--- a/IV/tests.sql
+++ b/IV/tests.sql
@@ -32,10 +32,10 @@ create table wm_figures (name text, way geometry);
 --   ogr2ogr -update -f PostgreSQL PG:"host=127.0.0.1 user=osm password=osm dbname=osm" fig8.gpkg
 -- to "normalize" a new line when it's in `f`:
 --   select st_astext(st_snaptogrid(st_transscale(geometry, -19.5, .016, 4000, 4000), 1)) from f;
-insert into wm_figures (name, way) values ('fig3',ST_GeomFromText('LINESTRING(0 0,12 0,13 4,20 2,20 0,32 0,33 10,38 16,43 15,44 10,44 0,60 0)'));
-insert into wm_figures (name, way) values ('fig3-1',ST_GeomFromText('LINESTRING(0 0,12 0,13 4,20 2,20 0,32 0,33 10,38 16,43 15,44 10,44 0)'));
-insert into wm_figures (name, way) values ('fig5',ST_GeomFromText('LINESTRING(0 39,19 52,27 77,26 104,41 115,49 115,65 103,65 75,53 45,63 15,91 0)'));
-insert into wm_figures (name, way) values ('fig6',ST_GeomFromText('LINESTRING(84 47,91 59,114 64,122 80,116 92,110 93,106 106,117 118,136 107,135 76,120 45,125 39,141 39,147 32)'));
+insert into wm_figures (name, way) values ('fig3','LINESTRING(0 0,12 0,13 4,20 2,20 0,32 0,33 10,38 16,43 15,44 10,44 0,60 0)'::geometry);
+insert into wm_figures (name, way) values ('fig3-1','LINESTRING(0 0,12 0,13 4,20 2,20 0,32 0,33 10,38 16,43 15,44 10,44 0)'::geometry);
+insert into wm_figures (name, way) values ('fig5','LINESTRING(0 39,19 52,27 77,26 104,41 115,49 115,65 103,65 75,53 45,63 15,91 0)'::geometry);
+insert into wm_figures (name, way) values ('fig6','LINESTRING(84 47,91 59,114 64,122 80,116 92,110 93,106 106,117 118,136 107,135 76,120 45,125 39,141 39,147 32)'::geometry);
 insert into wm_figures (name, way) values ('fig6-rev',ST_Reverse(ST_Translate((select way from wm_figures where name='fig6'), 60, 0)));
 insert into wm_figures (name, way) values ('fig6-combi',
   ST_Union(
@@ -43,12 +43,12 @@ insert into wm_figures (name, way) values ('fig6-combi',
       ST_Translate((select way from wm_figures where name='fig6'), 80, 90)
   )
 );
-insert into wm_figures (name, way) values('fig8', ST_GeomFromText('LINESTRING(173 12,174 10,180 8,186 8,186 13,191 11,189 6,201 5,203 11,216 16,216 6,222 7,229 3,236 2,239 6,243 8,248 6)'));
-insert into wm_figures (name, way) values ('inflection-1',ST_GeomFromText('LINESTRING(110 24,114 20,133 20,145 15,145 0,136 8,123 10,114 10,111 2)'));
-insert into wm_figures (name, way) values ('multi-island',ST_GeomFromText('MULTILINESTRING((-15 10,-10 10,-5 11,0 11,5 11,10 10,11 9,13 10,15 9),(-5 11,-2 15,0 16,2 15,5 11))'));
+insert into wm_figures (name, way) values('fig8', 'LINESTRING(173 12,174 10,180 8,186 8,186 13,191 11,189 6,201 5,203 11,216 16,216 6,222 7,229 3,236 2,239 6,243 8,248 6)'::geometry);
+insert into wm_figures (name, way) values ('inflection-1','LINESTRING(110 24,114 20,133 20,145 15,145 0,136 8,123 10,114 10,111 2)'::geometry);
+insert into wm_figures (name, way) values ('multi-island','MULTILINESTRING((-15 10,-10 10,-5 11,0 11,5 11,10 10,11 9,13 10,15 9),(-5 11,-2 15,0 16,2 15,5 11))'::geometry);
 
 -- TODO: there is a bug and it does not go through `self_crossing` function.
-insert into wm_figures (name, way) values ('selfcrossing-1',ST_GeomFromText('LINESTRING(-27 180,-20 166,-21 142,-18 136,55 136,55 136,71 145,44 165,37 146,22 145,14 164,11 164,3 146,-12 146,-13 176,-18 184)'));
+insert into wm_figures (name, way) values ('selfcrossing-1','LINESTRING(-27 180,-20 166,-21 142,-18 136,55 136,55 136,71 145,44 165,37 146,22 145,14 164,11 164,3 146,-12 146,-13 176,-18 184)'::geometry);
 insert into wm_figures (name, way) values ('selfcrossing-1-rev',ST_Reverse(ST_Translate((select way from wm_figures where name='selfcrossing-1'), 0, 60)));
 
 delete from wm_debug where name in (select distinct name from wm_figures);