function node_form($form, $form_state, $type) {
  $form['#theme_wrapper'][] = 'node_form_layout';
  $form['left'] = node_left_form($form, $form_state, $type);
  $form['right'] = node_right_form($form, $form_state, $type);
  $form['actions'] = node_actions_form($form, $form_state, $type);
  return $form;
}