diff --git a/demo/moulinrouge/tests.py b/demo/moulinrouge/tests.py
index 494dd88..161da67 100644
--- a/demo/moulinrouge/tests.py
+++ b/demo/moulinrouge/tests.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 # This file is part of pygal
-from pygal import Bar, Gauge, Pyramid, Funnel, Dot, CHARTS_BY_NAME
+from pygal import Bar, Gauge, Pyramid, Funnel, Dot, StackedBar, CHARTS_BY_NAME
 from pygal.style import styles
 
 
@@ -104,4 +104,11 @@ def get_test_routes(app):
         graph.add('2', [7, -4, 10, None, 8, 3, 1])
         return graph.render_response()
 
+    @app.route('/test/stacked')
+    def test_stacked():
+        stacked = StackedBar()
+        stacked.add('1', [1, 2, 3])
+        stacked.add('2', [4, 5, 6])
+        return stacked.render_response()
+
     return filter(lambda x: x.startswith('test'), locals())
diff --git a/pygal/ghost.py b/pygal/ghost.py
index 1b5f251..51db3e2 100644
--- a/pygal/ghost.py
+++ b/pygal/ghost.py
@@ -58,6 +58,8 @@ class Ghost(object):
 
     def add(self, title, values):
         """Add a serie to this graph"""
+        if not hasattr(values, '__iter__') and not isinstance(values, dict):
+            values = [values]
         self.raw_series.append((title, values))
 
     def _check(self):
diff --git a/pygal/graph/horizontal.py b/pygal/graph/horizontal.py
index e9b6fa8..87d8ad4 100644
--- a/pygal/graph/horizontal.py
+++ b/pygal/graph/horizontal.py
@@ -30,12 +30,6 @@ class HorizontalGraph(Graph):
         super(HorizontalGraph, self).__init__(*args, **kwargs)
 
     def _compute(self):
-        if self.x_labels:
-            self.x_labels = list(reversed(self.x_labels))
-
         super(HorizontalGraph, self)._compute()
         self._x_labels, self._y_labels = self._y_labels, self._x_labels
         self._box.swap()
-        # Y axis is inverted
-        for serie in self.series:
-            serie.values = list(reversed(serie.values))
diff --git a/pygal/graph/line.py b/pygal/graph/line.py
index ca494d6..d4a706b 100644
--- a/pygal/graph/line.py
+++ b/pygal/graph/line.py
@@ -90,11 +90,7 @@ class Line(Graph):
                 serie_node['plot'], view_values, close=self._self_close,
                 class_='line reactive' + (' nofill' if not self.fill else ''))
 
-    def _compute(self):
-        x_pos = [
-            x / (self._len - 1) for x in range(self._len)
-        ] if self._len != 1 else [.5]  # Center if only one value
-
+    def _points(self, x_pos):
         for serie in self.series:
             serie.points = [
                 (x_pos[i], v)
@@ -102,6 +98,13 @@ class Line(Graph):
             if self.interpolate:
                 serie.interpolated = self._interpolate(serie.values, x_pos)
 
+    def _compute(self):
+        x_pos = [
+            x / (self._len - 1) for x in range(self._len)
+        ] if self._len != 1 else [.5]  # Center if only one value
+
+        self._points(x_pos)
+
         if self.include_x_axis:
             self._box.ymin = min(self._min, 0)
             self._box.ymax = max(self._max, 0)
diff --git a/pygal/graph/stackedline.py b/pygal/graph/stackedline.py
index 5cd52fe..9b8bddc 100644
--- a/pygal/graph/stackedline.py
+++ b/pygal/graph/stackedline.py
@@ -20,7 +20,7 @@
 Stacked Line chart
 
 """
-
+from __future__ import division
 from pygal.graph.line import Line
 from pygal.adapters import none_to_zero
 
@@ -42,10 +42,7 @@ class StackedLine(Line):
         self._previous_line = values
         return new_values
 
-    def _compute(self):
-        x_pos = [
-            x / float(self._len - 1) for x in range(self._len)
-        ] if self._len != 1 else [.5]  # Center if only one value
+    def _points(self, x_pos):
         accumulation = [0] * self._len
         for serie in self.series:
             accumulation = map(sum, zip(accumulation, serie.values))
@@ -54,5 +51,3 @@ class StackedLine(Line):
                 for i, v in enumerate(accumulation)]
             if self.interpolate:
                 serie.interpolated = self._interpolate(accumulation, x_pos)
-
-        return super(StackedLine, self)._compute()
diff --git a/pygal/test/test_graph.py b/pygal/test/test_graph.py
index 509bd20..38071dd 100644
--- a/pygal/test/test_graph.py
+++ b/pygal/test/test_graph.py
@@ -103,6 +103,35 @@ def test_empty_lists(Chart):
     assert len(q(".legend")) == 2
 
 
+def test_non_iterable_value(Chart):
+    chart = Chart()
+    chart.add('A', 1)
+    chart.add('B', 2)
+    chart.x_labels = ('red', 'green', 'blue')
+    chart1 = chart.render()
+    chart = Chart()
+    chart.add('A', [1])
+    chart.add('B', [2])
+    chart.x_labels = ('red', 'green', 'blue')
+    chart2 = chart.render()
+    assert chart1 == chart2
+
+
+def test_iterable_types(Chart):
+    chart = Chart()
+    chart.add('A', [1, 2])
+    chart.add('B', [])
+    chart.x_labels = ('red', 'green', 'blue')
+    chart1 = chart.render()
+
+    chart = Chart()
+    chart.add('A', (1, 2))
+    chart.add('B', tuple())
+    chart.x_labels = ('red', 'green', 'blue')
+    chart2 = chart.render()
+    assert chart1 == chart2
+
+
 def test_values_by_dict(Chart):
     chart = Chart()
     chart.add('A', {'red': 10, 'green': 12, 'blue': 14})
diff --git a/pygal/test/test_stacked.py b/pygal/test/test_stacked.py
new file mode 100644
index 0000000..1739a10
--- /dev/null
+++ b/pygal/test/test_stacked.py
@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+# This file is part of pygal
+#
+# A python svg graph plotting library
+# Copyright © 2012 Kozea
+#
+# This library is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option) any
+# later version.
+#
+# This library is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with pygal. If not, see <http://www.gnu.org/licenses/>.
+from pygal import StackedLine
+
+
+def test_stacked_line():
+    stacked = StackedLine()
+    stacked.add('one_two', [1, 2])
+    stacked.add('ten_twelve', [10, 12])
+    q = stacked.render_pyquery()
+    assert set(q("desc.value").text().split(' ')) == set(
+        ('1', '2', '11', '14'))
+
+
+def test_stacked_line_log():
+    stacked = StackedLine(logarithmic=True)
+    stacked.add('one_two', [1, 2])
+    stacked.add('ten_twelve', [10, 12])
+    q = stacked.render_pyquery()
+    assert set(q("desc.value").text().split(' ')) == set(
+        ('1', '2', '11', '14'))
+
+
+def test_stacked_line_interpolate():
+    stacked = StackedLine(interpolate='cubic')
+    stacked.add('one_two', [1, 2])
+    stacked.add('ten_twelve', [10, 12])
+    q = stacked.render_pyquery()
+    assert set(q("desc.value").text().split(' ')) == set(
+        ('1', '2', '11', '14'))
diff --git a/pygal/util.py b/pygal/util.py
index 46929de..e5de874 100644
--- a/pygal/util.py
+++ b/pygal/util.py
@@ -312,6 +312,9 @@ def prepare_values(raw, config, cls):
                 if k in config.x_labels:
                     value_list[config.x_labels.index(k)] = v
             raw_values = value_list
+        else:
+            raw_values = list(raw_values)
+
         for index, raw_value in enumerate(
                 raw_values + (
                     (width - len(raw_values)) * [None]  # aligning values