diff --git a/Rakefile b/Rakefile
index cbf111a..92be6e2 100644
--- a/Rakefile
+++ b/Rakefile
@@ -3,83 +3,85 @@ require 'rake/clean'
 require 'open3'
 
 M2C = 'gm2' # Modula-2 compiler.
-BOOT_OBJECTS = FileList['source/*.elna']
-  .map do |source|
-    Pathname.new(source).basename.sub_ext('.o')
-  end
 
-directory 'build/boot'
+stage_compiler = Pathname.new 'build/stage1/elna'
+
+directory 'build/stage1'
+directory 'build/source'
 directory 'build/self'
 
 CLEAN.include 'build'
 
-rule(/build\/boot\/.+\.o$/ => ->(file) {
+rule(/build\/stage1\/.+\.o$/ => ->(file) {
   path = Pathname.new('source') + Pathname.new(file).basename
 
-  ['build/boot', path.sub_ext('.def'), path.sub_ext('.elna')]
+  ['build/stage1', path.sub_ext('.def'), path.sub_ext('.elna')]
 }) do |t|
   sources = t.prerequisites.filter { |f| f.end_with? '.elna' }
 
   sh M2C, '-fmod=.elna', '-c', '-I', 'source', '-o', t.name, *sources
 end
 
-rule(/build\/self\/.+\.o$/ => ->(file) {
-  path = Pathname.new(file).relative_path_from('build')
-  result = []
-
-  result << File.join('source', path.basename.sub_ext('.def'))
-  result << File.join('build', path.sub_ext('.mod'))
-}) do |t|
-  sources = t.prerequisites.filter { |f| f.end_with? '.mod' }
-
-  sh M2C, '-c', '-I', 'source', '-o', t.name, *sources
+file 'build/stage1/elna' => FileList['boot/stage1/source/*'].map { |file|
+  File.join 'build', 'stage1', Pathname.new(file).basename.sub_ext('.o')
+} do |t|
+  sh M2C, '-o', t.name, *t.prerequisites
 end
 
-rule(/build\/self\/.+\.mod$/ => [
-  'build/self', 'build/boot/Compiler',
-  ->(file) { File.join('source', Pathname.new(file).basename.sub_ext('.elna')) }
-]) do |t|
-  sources, compiler  = t.prerequisites
-    .reject { |f| File.directory? f }
-    .partition { |f| f.end_with? '.elna' }
-
-  File.open t.name, 'w' do |output|
-    puts
-    puts(compiler * ' ')
-
-    Open3.popen2(*compiler) do |cl_in, cl_out|
-      cl_in.write File.read(*sources)
-      cl_in.close
-
-      IO.copy_stream cl_out, output
-      cl_out.close
-    end
-  end
-end
-
-['boot', 'self'].each do |sub|
-  compiler_binary = Pathname.new('build') + sub + 'Compiler'
-
-  file compiler_binary.to_path => BOOT_OBJECTS.map { |file| File.join('build', sub, file) } do |t|
-    sh M2C, '-o', t.name, *t.prerequisites
-  end
-
-  compiler_object = compiler_binary.sub_ext('.o')
-end
-
-file 'build/boot/Compiler.o' => ['build/boot', 'source/Compiler.elna'] do |t|
+file 'build/stage1/Compiler.o' => ['build/stage1', 'source/Compiler.elna'] do |t|
   sources = t.prerequisites.filter { |f| f.end_with? '.elna' }
 
-  sh M2C, '-fscaffold-main', '-fmod=.elna', '-c', '-I', 'source', '-o', t.name, *sources
+  sh M2C, '-fscaffold-main', '-fmod=.elna', '-c', '-I', 'boot/stage1/source', '-o', t.name, *sources
 end
 
-file 'build/self/Compiler.o' => ['build/self/Compiler.mod'] do |t|
-  sources = t.prerequisites.filter { |f| f.end_with? '.mod' }
+['source', 'self'].each do |sub|
+  rule(/build\/#{sub}\/.+\.mod$/ => [
+    "build/#{sub}", stage_compiler.to_path,
+    ->(file) { File.join('source', Pathname.new(file).basename.sub_ext('.elna')) }
+  ]) do |t|
+    sources, compiler  = t.prerequisites
+      .reject { |f| File.directory? f }
+      .partition { |f| f.end_with? '.elna' }
 
-  sh M2C, '-fscaffold-main', '-c', '-I', 'source', '-o', t.name, *sources
+    File.open t.name, 'w' do |output|
+      puts
+      puts(compiler * ' ')
+
+      Open3.popen2(*compiler) do |cl_in, cl_out|
+        cl_in.write File.read(*sources)
+        cl_in.close
+
+        IO.copy_stream cl_out, output
+        cl_out.close
+      end
+    end
+  end
+
+  rule(/build\/#{sub}\/.+\.o$/ => ->(file) {
+    path = Pathname.new(file).relative_path_from('build')
+    result = []
+
+    result << File.join('source', path.basename.sub_ext('.def'))
+    result << File.join('build', path.sub_ext('.mod'))
+  }) do |t|
+    sources = t.prerequisites.filter { |f| f.end_with? '.mod' }
+
+    sh M2C, '-c', '-I', 'source', '-o', t.name, *sources
+  end
+
+  file "build/#{sub}/Compiler.o" => ["build/#{sub}/Compiler.mod"] do |t|
+    sh M2C, '-fscaffold-main', '-c', '-I', 'source', '-o', t.name, *t.prerequisites
+  end
+  stage_compiler = Pathname.new('build') + sub + 'elna'
+
+  file stage_compiler => FileList["source/*.elna"].map { |file|
+    File.join 'build', sub, Pathname.new(file).basename.sub_ext('.o')
+  } do |t|
+    sh M2C, '-o', t.name, *t.prerequisites
+  end
 end
 
-task default: 'build/self/Compiler'
+task default: 'build/self/elna'
 task default: 'build/self/Compiler.mod'
 task default: 'source/Compiler.elna'
 task :default do |t|