diff --git a/build.xml b/build.xml
index a152e85..ff919f1 100644
--- a/build.xml
+++ b/build.xml
@@ -47,9 +47,10 @@
 <target name="compose-tiles" depends="init-builddir,compile">
 <java classname="micropolisj.build_tool.MakeTiles" classpath="${builddir}"
 	fork="true" dir="graphics">
-	<arg file="graphics/tiles.dat" />
+	<arg file="graphics/tiles.rc" />
 	<arg file="${builddir}/tiles.png" />
 </java>
+<copy todir="${builddir}" file="graphics/tiles.rc" />
 </target>
 
 <target name="compile" depends="init-builddir">
diff --git a/graphics/tiles.dat b/graphics/tiles.rc
similarity index 100%
rename from graphics/tiles.dat
rename to graphics/tiles.rc
diff --git a/src/micropolisj/build_tool/MakeTiles.java b/src/micropolisj/build_tool/MakeTiles.java
index d8f5644..36202b9 100644
--- a/src/micropolisj/build_tool/MakeTiles.java
+++ b/src/micropolisj/build_tool/MakeTiles.java
@@ -1,5 +1,6 @@
 package micropolisj.build_tool;
 
+import micropolisj.engine.TileSpec;
 import java.awt.*;
 import java.awt.image.BufferedImage;
 import java.io.*;
diff --git a/src/micropolisj/build_tool/TileSpec.java b/src/micropolisj/engine/TileSpec.java
similarity index 98%
rename from src/micropolisj/build_tool/TileSpec.java
rename to src/micropolisj/engine/TileSpec.java
index 75f2497..9f1b40d 100644
--- a/src/micropolisj/build_tool/TileSpec.java
+++ b/src/micropolisj/engine/TileSpec.java
@@ -1,4 +1,4 @@
-package micropolisj.build_tool;
+package micropolisj.engine;
 
 import java.util.*;