diff --git a/examples/concept_v1.py b/examples/concept_v1.py
new file mode 100644
index 00000000..6f6567aa
--- /dev/null
+++ b/examples/concept_v1.py
@@ -0,0 +1,61 @@
+"""
+Concept example of objects catalogs.
+"""
+
+import objects
+import sqlite3
+
+
+# Some example classes.
+class A(object):
+    def __init__(self, db):
+        self.db = db
+
+
+class B(object):
+    def __init__(self, a, db):
+        self.a = a
+        self.db = db
+
+
+# Catalog of objects providers.
+class Catalog(objects.Catalog):
+    """
+    Objects catalog.
+    """
+
+    database = objects.Singleton(provides=sqlite3.Connection,
+                                 database=objects.KwArg('example.db'),
+                                 row_factory=objects.Attribute(sqlite3.Row))
+    """ :type: (objects.Provider) -> sqlite3.Connection """
+
+    object_a = objects.NewInstance(provides=A,
+                                   db=objects.KwArg(database))
+    """ :type: (objects.Provider) -> A """
+
+    object_b = objects.NewInstance(provides=B,
+                                   a=objects.KwArg(object_a),
+                                   db=objects.KwArg(database))
+    """ :type: (objects.Provider) -> B """
+
+
+# Catalog injection into consumer class.
+class Consumer(object):
+    catalog = Catalog(Catalog.object_a,
+                      Catalog.object_b)
+
+    def return_a_b(self):
+        return (self.catalog.object_a(),
+                self.catalog.object_b())
+
+a1, b1 = Consumer().return_a_b()
+
+
+# Catalog static provides.
+a2 = Catalog.object_a()
+b2 = Catalog.object_b()
+
+# Some asserts.
+assert a1 is not a2
+assert b1 is not b2
+assert a1.db is a2.db is b1.db is b2.db
diff --git a/examples/concept_v2.py b/examples/concept_v2.py
new file mode 100644
index 00000000..6af27742
--- /dev/null
+++ b/examples/concept_v2.py
@@ -0,0 +1,61 @@
+"""
+Concept example of objects catalogs.
+"""
+
+import objects
+import sqlite3
+
+
+# Some example classes.
+class A(object):
+    def __init__(self, db):
+        self.db = db
+
+
+class B(object):
+    def __init__(self, a, db):
+        self.a = a
+        self.db = db
+
+
+# Catalog of objects providers.
+class Catalog(objects.Catalog):
+    """
+    Objects catalog.
+    """
+
+    database = objects.Singleton(sqlite3.Connection,
+                                 objects.KwArg('database', ':memory:'),
+                                 objects.Attribute('row_factory', sqlite3.Row))
+    """ :type: (objects.Provider) -> sqlite3.Connection """
+
+    object_a = objects.NewInstance(A,
+                                   objects.KwArg('db', database))
+    """ :type: (objects.Provider) -> A """
+
+    object_b = objects.NewInstance(B,
+                                   objects.KwArg('a', object_a),
+                                   objects.KwArg('db', database))
+    """ :type: (objects.Provider) -> B """
+
+
+# Catalog injection into consumer class.
+class Consumer(object):
+    catalog = Catalog(Catalog.object_a,
+                      Catalog.object_b)
+
+    def return_a_b(self):
+        return (self.catalog.object_a(),
+                self.catalog.object_b())
+
+a1, b1 = Consumer().return_a_b()
+
+
+# Catalog static provides.
+a2 = Catalog.object_a()
+b2 = Catalog.object_b()
+
+# Some asserts.
+assert a1 is not a2
+assert b1 is not b2
+assert a1.db is a2.db is b1.db is b2.db