diff --git a/data_array.py b/data_array.py
new file mode 100644
index 0000000..ad5559b
--- /dev/null
+++ b/data_array.py
@@ -0,0 +1,29 @@
+import numpy as np
+import functools
+import operator
+
+class DataArray:
+    """Class holding information on ndarray"""
+    def __init__(self, data, spatial_axes, components_order='C'):
+        self.data = data
+        axes = list(range(data.ndim))
+        for ax in spatial_axes:
+            axes.remove(ax)
+
+        nb_components = functools.reduce(lambda x, y: x * data.shape[y], axes, 1)
+
+        if components_order == 'C':
+            axes.reverse()
+        else:
+            raise Exception('Unrecognized components order')
+
+        axes += spatial_axes
+
+        self.flat_data = np.ravel(np.transpose(self.data, axes=axes), order='F')
+        self.attributes = {
+            "type": str(self.flat_data.dtype).capitalize(),
+            "NumberOfComponents": nb_components
+        }
+
+    def __str__(self):
+        return self.attributes.__str__()
diff --git a/test.py b/test.py
new file mode 100644
index 0000000..d775ed6
--- /dev/null
+++ b/test.py
@@ -0,0 +1,21 @@
+from writer import *
+from data_array import *
+import numpy as np
+
+writer = Writer('RectilinearGrid')
+writer.setDataNodeAttributes({
+    "WholeExtent": "0 1 0 1 0 1"
+})
+
+piece = writer.registerPiece({
+    "Extent": "0 1 0 1 0 1"
+})
+
+coordinates = piece.register('Coordinates')
+
+array = np.array([[0, 0, 0], [1, 1, 1]])
+print(type(array.dtype))
+data_array = DataArray(array, [ 1])
+print(data_array)
+
+print(writer)
diff --git a/writer.py b/writer.py
index ba9a576..4b52e0c 100644
--- a/writer.py
+++ b/writer.py
@@ -1,49 +1,49 @@
 import xml.dom
 import xml.dom.minidom as dom
 
 import sys
 
 def setAttributes(node, attributes):
     """Set attributes of a node"""
     map(lambda x: node.setAttribute(*x), attributes.items())
 
 class Component:
     """Generic component class capable of registering sub-components"""
     def __init__(self, name, parent_node, document):
         self.node = document.createElement(name)
         self.document = document
         parent_node.appendChild(self.node)
 
 
-    def register(self, name, attributes):
+    def register(self, name, attributes=dict()):
         """Register a sub-component"""
         sub_component = Component(name, self.node, self.document)
         setAttributes(sub_component.node, attributes)
         return sub_component
 
 
 class Writer:
     """Generic XML handler for VTK files"""
     def __init__(self, vtk_format, vtk_version='0.1', byte_order='LittleEndian'):
         self.document = dom.getDOMImplementation().createDocument(None, 'VTKFile', None)
         self.root = self.document.documentElement
         self.root.setAttribute('type', vtk_format)
         self.root.setAttribute('version', vtk_version)
         self.root.setAttribute('byte_order', byte_order)
         self.data_node = self.document.createElement(vtk_format)
         self.root.appendChild(self.data_node)
 
     def setDataNodeAttributes(self, attributes):
         """Set attributes for the entire dataset"""
         setAttributes(self.data_node, attributes)
 
     def registerPiece(self, attributes):
         """Register a piece element"""
         piece = Component('Piece', self.data_node, self.document)
         setAttributes(piece.node, attributes)
         return piece
 
     def __str__(self):
         """Print XML to string"""
         return self.document.toprettyxml()