diff --git a/lib/instancevalue.rb b/lib/instancevalue.rb
index ad11b11..c8c1e08 100644
--- a/lib/instancevalue.rb
+++ b/lib/instancevalue.rb
@@ -22,7 +22,7 @@
 #     person.age                                    #=> age at runtime
 #     person.instance_eval{val :birthday, Time.now} #=> Exception
 module InstanceValue
-  VERSION = '0.0.2'.freeze
+  VERSION = '0.0.3'.freeze
 
   module Eigen
     private
@@ -73,6 +73,11 @@ def instance_values
   
   private
   
+  def initialize_copy(original)
+    singleton_class.const_set :VALUES,
+      original.singleton_class::VALUES.dup
+  end
+  
   def remove_instance_value(name)
     if instance_value_defined? name
       singleton_class::VALUES.delete name.to_sym
diff --git a/test/test_instancevalue.rb b/test/test_instancevalue.rb
index ac40041..a099ad3 100644
--- a/test/test_instancevalue.rb
+++ b/test/test_instancevalue.rb
@@ -40,4 +40,26 @@ def test_normaly
       person.name
     end
   end
+  
+  def test_dup
+    person = Person.new Time.now
+    person2 = person.dup
+    
+    assert_equal person.instance_values, person2.instance_values
+    
+    person2.instance_value_set :newer, 123
+    
+    assert_same false, (person.instance_values == person2.instance_values)
+  end
+  
+  def test_clone
+    person = Person.new Time.now
+    person2 = person.clone
+    
+    assert_equal person.instance_values, person2.instance_values
+    
+    person2.instance_value_set :newer, 123
+    
+    assert_same false, (person.instance_values == person2.instance_values)
+  end
 end