diff --git a/.pyup.yml b/.pyup.yml
new file mode 100644
index 0000000..604f69f
--- /dev/null
+++ b/.pyup.yml
@@ -0,0 +1,4 @@
+# autogenerated pyup.io config file 
+# see https://pyup.io/docs/configuration/ for all available options
+
+update: insecure
diff --git a/.travis.yml b/.travis.yml
index ae09065..22a95b2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,6 +21,8 @@ script:
 - tox -e $TOX_ENV
 after_success:
 - coveralls
+- pip install codecov
+- codecov
 before_script: flake8 --ignore=W391 stl tests
 notifications:
   email:
diff --git a/README.rst b/README.rst
index b807673..ff263d8 100644
--- a/README.rst
+++ b/README.rst
@@ -341,16 +341,17 @@ Combining multiple STL files
 
 
     def translate(_solid, step, padding, multiplier, axis):
-        if axis == 'x':
-            items = [0, 3, 6]
-        elif axis == 'y':
-            items = [1, 4, 7]
-        elif axis == 'z':
-            items = [2, 5, 8]
-        for p in _solid.points:
-            # point items are ((x, y, z), (x, y, z), (x, y, z))
-            for i in range(3):
-                p[items[i]] += (step * multiplier) + (padding * multiplier)
+        if 'x' == axis:
+            items = 0, 3, 6
+        elif 'y' == axis:
+            items = 1, 4, 7
+        elif 'z' == axis:
+            items = 2, 5, 8
+        else:
+            raise RuntimeError('Unknown axis %r, expected x, y or z' % axis)
+
+        # _solid.points.shape == [:, ((x, y, z), (x, y, z), (x, y, z))]
+        _solid.points[:, items] += (step * multiplier) + (padding * multiplier)
 
 
     def copy_obj(obj, dims, num_rows, num_cols, num_layers):
diff --git a/pytest.ini b/pytest.ini
index a8eb3e4..4abc3f8 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,6 +1,8 @@
 [pytest]
 basetemp = tmp
 
+doctest_optionflags = NORMALIZE_WHITESPACE
+
 python_files =
     stl/*.py
     tests/*.py
@@ -21,3 +23,8 @@ pep8ignore =
 
 flakes-ignore =
     docs/*.py ALL
+
+looponfailroots =
+    stl
+    tests
+    build
diff --git a/setup.py b/setup.py
index 411c838..0ffe600 100644
--- a/setup.py
+++ b/setup.py
@@ -8,22 +8,40 @@
 
 setup_kwargs = {}
 
+
+def error(*lines):
+    for line in lines:
+        print(line, file=sys.stderr)
+
+
 try:
-    import numpy
-    from Cython import Build
-
-    setup_kwargs['ext_modules'] = Build.cythonize([
-        extension.Extension(
-            'stl._speedups',
-            ['stl/_speedups.pyx'],
-            include_dirs=[numpy.get_include()],
-        ),
-    ])
+    from stl import stl
+    if not hasattr(stl, 'BaseStl'):
+        error('ERROR',
+              'You have an incompatible stl package installed'
+              'Please run "pip uninstall -y stl" first')
+        sys.exit(1)
 except ImportError:
-    print('WARNING', file=sys.stderr)
-    print('Cython and Numpy is required for building extension.',
-          file=sys.stderr)
-    print('Falling back to pure Python implementation.', file=sys.stderr)
+    pass
+
+
+if sys.version_info.major == 2 or sys.platform.lower() != 'win32':
+    try:
+        import numpy
+        from Cython import Build
+
+        setup_kwargs['ext_modules'] = Build.cythonize([
+            extension.Extension(
+                'stl._speedups',
+                ['stl/_speedups.pyx'],
+                include_dirs=[numpy.get_include()],
+            ),
+        ])
+    except ImportError:
+        error('WARNING',
+              'Cython and Numpy is required for building extension.',
+              'Falling back to pure Python implementation.')
+
 
 # To prevent importing about and thereby breaking the coverage info we use this
 # exec hack
@@ -40,7 +58,6 @@
 
 install_requires = [
     'numpy',
-    'nine',
     'python-utils>=1.6.2',
 ]
 
diff --git a/stl/__about__.py b/stl/__about__.py
index 728ddf9..68dc6ee 100644
--- a/stl/__about__.py
+++ b/stl/__about__.py
@@ -1,6 +1,6 @@
 __package_name__ = 'numpy-stl'
 __import_name__ = 'stl'
-__version__ = '2.3.2'
+__version__ = '2.4.0'
 __author__ = 'Rick van Hattem'
 __author_email__ = 'Wolph@Wol.ph'
 __description__ = ' '.join('''
diff --git a/stl/base.py b/stl/base.py
index 39e6123..bad215e 100644
--- a/stl/base.py
+++ b/stl/base.py
@@ -106,23 +106,23 @@ class BaseMesh(logger.Logged, collections.Mapping):
 
     >>> # Check item 0 (contains v0, v1 and v2)
     >>> mesh[0]
-    array([ 1.,  1.,  1.,  2.,  2.,  2.,  0.,  0.,  0.], dtype=float32)
-    >>> mesh.vectors[0] # doctest: +NORMALIZE_WHITESPACE
-    array([[ 1.,  1.,  1.],
-           [ 2.,  2.,  2.],
-           [ 0.,  0.,  0.]], dtype=float32)
+    array([1., 1., 1., 2., 2., 2., 0., 0., 0.], dtype=float32)
+    >>> mesh.vectors[0]
+    array([[1., 1., 1.],
+           [2., 2., 2.],
+           [0., 0., 0.]], dtype=float32)
     >>> mesh.v0[0]
-    array([ 1.,  1.,  1.], dtype=float32)
+    array([1., 1., 1.], dtype=float32)
     >>> mesh.points[0]
-    array([ 1.,  1.,  1.,  2.,  2.,  2.,  0.,  0.,  0.], dtype=float32)
-    >>> mesh.data[0] # doctest: +NORMALIZE_WHITESPACE
-    ([ 0.,  0.,  0.], [[ 1.,  1.,  1.], [ 2.,  2.,  2.], [ 0.,  0.,  0.]], [0])
+    array([1., 1., 1., 2., 2., 2., 0., 0., 0.], dtype=float32)
+    >>> mesh.data[0]
+    ([0., 0., 0.], [[1., 1., 1.], [2., 2., 2.], [0., 0., 0.]], [0])
     >>> mesh.x[0]
-    array([ 1.,  2.,  0.], dtype=float32)
+    array([1., 2., 0.], dtype=float32)
 
     >>> mesh[0] = 3
     >>> mesh[0]
-    array([ 3.,  3.,  3.,  3.,  3.,  3.,  3.,  3.,  3.], dtype=float32)
+    array([3., 3., 3., 3., 3., 3., 3., 3., 3.], dtype=float32)
 
     >>> len(mesh) == len(list(mesh))
     True
@@ -315,6 +315,17 @@ def update_areas(self):
         areas = .5 * numpy.sqrt((self.normals ** 2).sum(axis=1))
         self.areas = areas.reshape((areas.size, 1))
 
+    def check(self):
+        if (self.normals.sum(axis=0) >= 1e-4).any():
+            self.warning('''
+            Your mesh is not closed, the mass methods will not function
+            correctly on this mesh.  For more info:
+            https://github.com/WoLpH/numpy-stl/issues/69
+            '''.strip())
+            return False
+        else:
+            return True
+
     def get_mass_properties(self):
         '''
         Evaluate and return a tuple with the following elements:
@@ -325,6 +336,8 @@ def get_mass_properties(self):
         Documentation can be found here:
         http://www.geometrictools.com/Documentation/PolyhedralMassProperties.pdf
         '''
+        self.check()
+
         def subexpression(x):
             w0, w1, w2 = x[:, 0], x[:, 1], x[:, 2]
             temp0 = w0 + w1
@@ -421,7 +434,7 @@ def rotation_matrix(cls, axis, theta):
                             [2 * (bc - ad), aa + cc - bb - dd, 2 * (cd + ab)],
                             [2 * (bd + ac), 2 * (cd - ab), aa + dd - bb - cc]])
 
-    def rotate(self, axis, theta, point=None):
+    def rotate(self, axis, theta=0, point=None):
         '''
         Rotate the matrix over the given axis by the given theta (angle)
 
@@ -442,6 +455,13 @@ def rotate(self, axis, theta, point=None):
         if not theta:
             return
 
+        self.rotate_using_matrix(self.rotation_matrix(axis, theta), point)
+
+    def rotate_using_matrix(self, rotation_matrix, point=None):
+        # No need to rotate if there is no actual rotation
+        if not rotation_matrix.any():
+            return
+
         if isinstance(point, (numpy.ndarray, list, tuple)) and len(point) == 3:
             point = numpy.asarray(point)
         elif point is None:
@@ -451,12 +471,6 @@ def rotate(self, axis, theta, point=None):
         else:
             raise TypeError('Incorrect type for point', point)
 
-        rotation_matrix = self.rotation_matrix(axis, theta)
-
-        # No need to rotate if there is no actual rotation
-        if not rotation_matrix.any():
-            return
-
         def _rotate(matrix):
             if point.any():
                 # Translate while rotating
diff --git a/stl/stl.py b/stl/stl.py
index c96525d..b446ef5 100644
--- a/stl/stl.py
+++ b/stl/stl.py
@@ -214,7 +214,9 @@ def get(prefix=''):
 
     @classmethod
     def _load_ascii(cls, fh, header, speedups=True):
-        if _speedups and speedups:
+        # The speedups module is covered by travis but it can't be tested in
+        # all environments, this makes coverage checks easier
+        if _speedups and speedups:  # pragma: no cover
             return _speedups.ascii_read(fh, header)
         else:
             iterator = cls._ascii_reader(fh, header)
@@ -259,7 +261,7 @@ def save(self, filename, fh=None, mode=AUTOMATIC, update_normals=True):
             pass
 
     def _write_ascii(self, fh, name):
-        if _speedups and self.speedups:
+        if _speedups and self.speedups:  # pragma: no cover
             _speedups.ascii_write(fh, b(name), self.data)
         else:
             def p(s, file):
diff --git a/tests/stl_corruption.py b/tests/stl_corruption.py
index aa6f5e8..f9c2b97 100644
--- a/tests/stl_corruption.py
+++ b/tests/stl_corruption.py
@@ -1,4 +1,5 @@
 from __future__ import print_function
+import numpy
 import pytest
 import struct
 
@@ -127,3 +128,17 @@ def test_corrupt_binary_file(tmpdir, speedups):
         fh.seek(0)
         mesh.Mesh.from_file(str(tmp_file), fh=fh, speedups=speedups)
 
+
+def test_duplicate_polygons():
+    data = numpy.zeros(3, dtype=mesh.Mesh.dtype)
+    data['vectors'][0] = numpy.array([[0, 0, 0],
+                                      [1, 0, 0],
+                                      [0, 1, 1.]])
+    data['vectors'][0] = numpy.array([[0, 0, 0],
+                                      [2, 0, 0],
+                                      [0, 2, 1.]])
+    data['vectors'][0] = numpy.array([[0, 0, 0],
+                                      [3, 0, 0],
+                                      [0, 3, 1.]])
+
+    assert not mesh.Mesh(data, remove_empty_areas=False).check()
diff --git a/tests/test_rotate.py b/tests/test_rotate.py
index 374b656..65900ea 100644
--- a/tests/test_rotate.py
+++ b/tests/test_rotate.py
@@ -94,6 +94,27 @@ def test_rotation_over_point():
         mesh.rotate([1, 0, 0], math.radians(180), point='x')
 
 
+def test_double_rotation():
+    # Create a single face
+    data = numpy.zeros(1, dtype=Mesh.dtype)
+
+    data['vectors'][0] = numpy.array([[1, 0, 0],
+                                      [0, 1, 0],
+                                      [0, 0, 1]])
+
+    mesh = Mesh(data, remove_empty_areas=False)
+
+    rotation_matrix = mesh.rotation_matrix([1, 0, 0], math.radians(180))
+    combined_rotation_matrix = numpy.dot(rotation_matrix, rotation_matrix)
+
+    mesh.rotate_using_matrix(combined_rotation_matrix)
+    utils.array_equals(
+        mesh.vectors,
+        numpy.array([[[1., 0., 0.],
+                      [0., 1., 0.],
+                      [0., 0., 1.]]]))
+
+
 def test_no_rotation():
     # Create a single face
     data = numpy.zeros(1, dtype=Mesh.dtype)