diff --git a/doc/manual/development/changelog.rst b/doc/manual/development/changelog.rst
index dc12a2076..1002ecf90 100644
--- a/doc/manual/development/changelog.rst
+++ b/doc/manual/development/changelog.rst
@@ -3,6 +3,14 @@
 Changelog
 =========
 
+Upcoming version 
+****************
+
+Pull Request #379 from godardma (27/04)
+---------------------------------------
+
+``Zonotope`` and ``Parallelepiped`` center is now ``c`` instead of ``z`` to avoid ambiguity.
+
 Version 2.0.2
 *************
 
diff --git a/doc/manual/manual/geometry/zonotope.png b/doc/manual/manual/geometry/zonotope.png
index fb74b6718..cc0584583 100644
Binary files a/doc/manual/manual/geometry/zonotope.png and b/doc/manual/manual/geometry/zonotope.png differ
diff --git a/doc/manual/manual/geometry/zonotope.rst b/doc/manual/manual/geometry/zonotope.rst
index 2fe1f1354..a0471be64 100644
--- a/doc/manual/manual/geometry/zonotope.rst
+++ b/doc/manual/manual/geometry/zonotope.rst
@@ -16,13 +16,13 @@ A zonotope is a convex and symmetric polytope.
 It can be represented as the Minkowski sum of a finite number of line segments, which are called its generators.
 
 In Codac, zonotopes are represented by the class :class:`Zonotope`. A zonotope is defined by its center and its generators.
-The center is a :class:`Vector`, noted :math:`z`, and the generators are stored in a :class:`Matrix`, noted :math:`A`. 
+The center is a :class:`Vector`, noted :math:`\mathbf{c}`, and the generators are stored in a :class:`Matrix`, noted :math:`\mathbf{A}`. 
 Each column of the matrix corresponds to a generator.
 
 The resulting zonotope is:
 
 .. math::
-  Z = z + A \cdot [-1,1]^m
+  Z = \mathbf{c} + \mathbf{A} \cdot [-1,1]^m
 
 Where :math:`m` is the number of generators (i.e., the number of columns of the matrix :math:`A`).
 
@@ -37,24 +37,24 @@ It can be constructed in Codac as follows:
   
   .. code-tab:: py
 
-    z = Vector([1,2])
+    c = Vector([1,2])
     A = Matrix([[1,0,2],[0,1,1]])
 
-    Z = Zonotope(z, A)
+    Z = Zonotope(c, A)
 
   .. code-tab:: c++
 
-    Vector z({1,2});
+    Vector c({1,2});
     Matrix A({{1,0,2},{0,1,1}});
 
-    Zonotope Z(z, A);
+    Zonotope Z(c, A);
 
   .. code-tab:: matlab
 
-    z = Vector({1,2});
+    c = Vector({1,2});
     A = Matrix({{1,0,2},{0,1,1}});
 
-    Z = Zonotope(z,A);
+    Z = Zonotope(c,A);
 
 The resulting zonotope is represented in the figure below:
 
diff --git a/python/src/core/domains/zonotope/codac2_py_Zonotope.cpp b/python/src/core/domains/zonotope/codac2_py_Zonotope.cpp
index 7b0977919..ab4e578f1 100644
--- a/python/src/core/domains/zonotope/codac2_py_Zonotope.cpp
+++ b/python/src/core/domains/zonotope/codac2_py_Zonotope.cpp
@@ -39,8 +39,12 @@ void export_Zonotope(py::module& m)
       ZONOTOPE_ZONOTOPE_PROJ_CONST_VECTOR_INDEX_REF_CONST,
       "indices"_a)
 
-    .def_readwrite("z", &Zonotope::z,
-      VECTOR_ZONOTOPE_Z)
+    .def("__add__", &Zonotope::operator+,
+      ZONOTOPE_ZONOTOPE_OPERATORPLUS_CONST_ZONOTOPE_REF,
+      py::is_operator())
+
+    .def_readwrite("c", &Zonotope::c,
+      VECTOR_ZONOTOPE_C)
 
     .def_readwrite("A", &Zonotope::A,
       MATRIX_ZONOTOPE_A)
diff --git a/python/src/graphics/figures/codac2_py_Figure3D.cpp b/python/src/graphics/figures/codac2_py_Figure3D.cpp
index 24dbf165f..58068aba5 100644
--- a/python/src/graphics/figures/codac2_py_Figure3D.cpp
+++ b/python/src/graphics/figures/codac2_py_Figure3D.cpp
@@ -35,8 +35,8 @@ void export_Figure3D(py::module& m)
       CONST_STRING_REF_FIGURE3D_NAME_CONST)
 
     .def("draw_axes", &Figure3D::draw_axes,
-      VOID_FIGURE3D_DRAW_AXES_DOUBLE,
-      "size"_a=1.0)
+      VOID_FIGURE3D_DRAW_AXES_DOUBLE_CONST_VECTOR_REF,
+      "size"_a=1.0, "origin"_a=py::none())
 
     // Geometric shapes
     .def("draw_triangle", (void(Figure3D::*)(const Vector &c, const Matrix &A, const Vector &p1, const Vector &p2, const Vector &p3, const StyleProperties &s))&Figure3D::draw_triangle,
diff --git a/src/core/domains/zonotope/codac2_Parallelepiped.cpp b/src/core/domains/zonotope/codac2_Parallelepiped.cpp
index ef75b58fa..280ff0896 100644
--- a/src/core/domains/zonotope/codac2_Parallelepiped.cpp
+++ b/src/core/domains/zonotope/codac2_Parallelepiped.cpp
@@ -12,29 +12,29 @@
 
 using namespace codac2;
 
-Parallelepiped::Parallelepiped(const Vector& z_, const Matrix& A_)
-  : Zonotope(z_, A_)
+Parallelepiped::Parallelepiped(const Vector& c_, const Matrix& A_)
+  : Zonotope(c_, A_)
 {
-  assert_release(A.cols() <= z.size() && "too many vectors, you are describing a zonotope");
+  assert_release(A.cols() <= c.size() && "too many vectors, you are describing a zonotope");
 }
 
-void generate_vertices(Index i, Index n, const Vector& z, const Matrix& A, std::vector<Vector>& L_v)
+void generate_vertices(Index i, Index n, const Vector& c, const Matrix& A, std::vector<Vector>& L_v)
 {
   if (i == n)
   {
-    L_v.push_back(z);
+    L_v.push_back(c);
   }
   else if (i<n)
   {
-    generate_vertices(i+1, n, z + A.col(i), A, L_v);
-    generate_vertices(i+1, n, z - A.col(i), A, L_v);
+    generate_vertices(i+1, n, c + A.col(i), A, L_v);
+    generate_vertices(i+1, n, c - A.col(i), A, L_v);
   }
 }
 
 std::vector<Vector> Parallelepiped::vertices() const
 {
   std::vector<Vector> L_v;
-  generate_vertices(0, z.size(),z,A,L_v);
+  generate_vertices(0, c.size(),c,A,L_v);
   return L_v;
 }
 
@@ -46,9 +46,9 @@ BoolInterval Parallelepiped::contains(const Vector& v) const
 BoolInterval Parallelepiped::is_superset(const IntervalVector& x) const
 {
   assert_release(A.rows() == A.cols() && "Matrix A must be square to check containment.");
-  assert_release(x.size() == z.size() && "Point dimension must match parallelepiped dimension.");
+  assert_release(x.size() == c.size() && "Point dimension must match parallelepiped dimension.");
 
-  IntervalVector B = inverse_enclosure(A)*(x - z);
+  IntervalVector B = inverse_enclosure(A)*(x - c);
   IntervalVector IV = IntervalVector::constant(A.cols(),{-1,1});
 
   if (!(B.intersects(IV)))
diff --git a/src/core/domains/zonotope/codac2_Parallelepiped.h b/src/core/domains/zonotope/codac2_Parallelepiped.h
index 19b6d9338..20e17bff1 100644
--- a/src/core/domains/zonotope/codac2_Parallelepiped.h
+++ b/src/core/domains/zonotope/codac2_Parallelepiped.h
@@ -21,9 +21,9 @@ namespace codac2
   /**
    * \class Parallelepiped
    * 
-   * \brief Class representing a parallelepiped \f$\mathbf{z} + \mathbf{A}\cdot[-1,1]^m\f$
+   * \brief Class representing a parallelepiped \f$\mathbf{c} + \mathbf{A}\cdot[-1,1]^m\f$
    * 
-   * This class represents a parallelepiped in n-dimensional space, defined by a center point \f$\mathbf{z}\f$ and a shape matrix \f$\mathbf{A}\f$.
+   * This class represents a parallelepiped in n-dimensional space, defined by a center point \f$\mathbf{c}\f$ and a shape matrix \f$\mathbf{A}\f$.
    * 
    * A parallelepiped is a special case of a zonotope where the shape matrix \f$\mathbf{A}\f$ has \f$m\f$ columns with \f$m \leqslant n\f$.
    */
@@ -34,10 +34,10 @@ namespace codac2
       /**
        * \brief Constructs a n-parallelepiped object with a given center and shape matrix
        * 
-       * \param z Center of the parallelepiped (n-dimensional vector)
+       * \param c Center of the parallelepiped (n-dimensional vector)
        * \param A Shape matrix of the parallelepiped (\f$n\times m\f$ matrix with \f$m \leqslant n\f$)
        */
-      Parallelepiped(const Vector& z, const Matrix& A);
+      Parallelepiped(const Vector& c, const Matrix& A);
       
       /**
        * \brief Computes the vertices of the parallelepiped
diff --git a/src/core/domains/zonotope/codac2_Zonotope.cpp b/src/core/domains/zonotope/codac2_Zonotope.cpp
index 9091e7f4d..8eb9dabe8 100644
--- a/src/core/domains/zonotope/codac2_Zonotope.cpp
+++ b/src/core/domains/zonotope/codac2_Zonotope.cpp
@@ -11,31 +11,42 @@
 
 using namespace codac2;
 
-Zonotope::Zonotope(const Vector& z_, const Matrix& A_)
-  : z(z_), A(A_)
+Zonotope::Zonotope(const Vector& c_, const Matrix& A_)
+  : c(c_), A(A_)
 {
-  assert_release(z.size() == A.rows());
+  assert_release(c.size() == A.rows());
 }
 
 IntervalVector Zonotope::box() const
 {
-  return z + (A.template cast<Interval>())*IntervalVector::constant(A.cols(),{-1,1});
+  return c + (A.template cast<Interval>())*IntervalVector::constant(A.cols(),{-1,1});
 }
 
 Zonotope Zonotope::proj(const std::vector<Index>& indices) const
 {
   assert_release(*std::min_element(indices.begin(), indices.end()) >= 0 && "indices out of range");
-  assert_release(*std::max_element(indices.begin(), indices.end()) <= z.size() && "indices out of range");
+  assert_release(*std::max_element(indices.begin(), indices.end()) <= c.size() && "indices out of range");
 
   Matrix A_cropped (indices.size(), A.cols());
-  Vector z_cropped (indices.size());
+  Vector c_cropped (indices.size());
 
   for (size_t i = 0; i < indices.size(); ++i)
   {
     A_cropped.row(i) = A.row(indices[i]);
-    z_cropped[i] = z[indices[i]];
+    c_cropped[i] = c[indices[i]];
   }
 
-  return Zonotope(z_cropped, A_cropped);
+  return Zonotope(c_cropped, A_cropped);
 }
 
+Zonotope Zonotope::operator+(const Zonotope& zonotope)
+{
+  assert_release(c.size() == zonotope.c.size() && "Zonotopes must have the same dimension");
+
+  Vector c_sum = c + zonotope.c;
+  Matrix A_sum (A.rows(), A.cols() + zonotope.A.cols());
+
+  A_sum << A, zonotope.A;
+
+  return Zonotope(c_sum, A_sum);
+}
diff --git a/src/core/domains/zonotope/codac2_Zonotope.h b/src/core/domains/zonotope/codac2_Zonotope.h
index 863a2681b..ad1255b61 100644
--- a/src/core/domains/zonotope/codac2_Zonotope.h
+++ b/src/core/domains/zonotope/codac2_Zonotope.h
@@ -18,11 +18,11 @@ namespace codac2
 {
   /**
    * \class Zonotope
-   * \brief Class representing a zonotope \f$\mathbf{z} + \mathbf{A}\cdot[-1,1]^m\f$
+   * \brief Class representing a zonotope \f$\mathbf{c} + \mathbf{A}\cdot[-1,1]^m\f$
    * 
-   * This class represents a zonotope in n-dimensional space, defined by a center point \f$\mathbf{z}\f$ and a shape matrix \f$\mathbf{A}\f$.
+   * This class represents a zonotope in n-dimensional space, defined by a center point \f$\mathbf{c}\f$ and a shape matrix \f$\mathbf{A}\f$.
    * 
-   * The vector \f$\mathbf{z}\f$ and each column of the matrix \f$\mathbf{A}\f$ must have the same dimension \f$n\f$, but the matrix \f$\mathbf{A}\f$ can have any number of columns \f$m\f$.
+   * The vector \f$\mathbf{c}\f$ and each column of the matrix \f$\mathbf{A}\f$ must have the same dimension \f$n\f$, but the matrix \f$\mathbf{A}\f$ can have any number of columns \f$m\f$.
    */
   class Zonotope
   {
@@ -31,10 +31,10 @@ namespace codac2
       /**
        * \brief Constructs a n-zonotope object with a given center and shape matrix
        * 
-       * \param z Center of the zonotope (n-dimensional vector)
+       * \param c Center of the zonotope (n-dimensional vector)
        * \param A Shape matrix of the zonotope (\f$n\times m\f$ matrix)
        */
-      Zonotope(const Vector& z, const Matrix& A);
+      Zonotope(const Vector& c, const Matrix& A);
 
       /**
        * \brief Computes the axis-aligned bounding box of the zonotope
@@ -52,10 +52,19 @@ namespace codac2
        */
       Zonotope proj(const std::vector<Index>& indices) const;
 
+      /**
+       * \brief Computes the Minkowski sum of this Zonotope with another Zonotope
+       * 
+       * \param zonotope The other Zonotope to add to this one
+       * 
+       * \return A new Zonotope object representing the Minkowski sum of the two Zonotopes
+       */
+      Zonotope operator+(const Zonotope& zonotope);
+
       /**
        * \brief Center of the zonotope
        */
-      Vector z;
+      Vector c;
 
       /**
        * \brief Shape matrix of the zonotope
diff --git a/src/core/functions/analytic/codac2_AnalyticFunction.h b/src/core/functions/analytic/codac2_AnalyticFunction.h
index 337a64d03..0fe6fd645 100644
--- a/src/core/functions/analytic/codac2_AnalyticFunction.h
+++ b/src/core/functions/analytic/codac2_AnalyticFunction.h
@@ -220,17 +220,17 @@ namespace codac2
                     "Parallelepiped evaluation requires at least one input.");
 
         IntervalVector Y = this->eval(((typename Wrapper<Args>::Domain)(x)).mid()...);
-        Vector z = Y.mid();
+        Vector c = Y.mid();
 
         Matrix A = this->diff(((typename Wrapper<Args>::Domain)(x)).mid()...).mid();
 
         // Maximum error computation
-        double rho = error_peibos(Y, z, this->diff(x...), A, cart_prod(x...));
+        double rho = error_peibos(Y, c, this->diff(x...), A, cart_prod(x...));
 
         // Inflation of the parallelepiped
         Matrix A_inf = inflate_flat_parallelepiped(A, (cart_prod(x...).template cast<Interval>()).rad(), rho);
 
-        return Parallelepiped(z, A_inf);
+        return Parallelepiped(c, A_inf);
       }
 
       Index output_size() const
diff --git a/src/graphics/figures/codac2_Figure2D.cpp b/src/graphics/figures/codac2_Figure2D.cpp
index 53045ebc1..33cbb962b 100644
--- a/src/graphics/figures/codac2_Figure2D.cpp
+++ b/src/graphics/figures/codac2_Figure2D.cpp
@@ -255,7 +255,7 @@ void Figure2D::draw_zonotope(const Zonotope& z, const StyleProperties& style)
        }
    }
    vector<Vector> vertices;
-   Vector point=z.z;
+   Vector point=z.c;
    // Start from v[1] maximum (and v[0] min for horizontal side)
    for (const auto& a : sides) {
        point+=a.second;
@@ -277,17 +277,17 @@ void Figure2D::draw_zonotope(const Zonotope& z, const StyleProperties& style)
 
 void Figure2D::draw_parallelepiped(const Parallelepiped& p, const StyleProperties& style)
 {
-  assert_release(p.A.is_squared() && p.A.rows() == p.z.size());
-  assert_release(p.z.size() == 2);
+  assert_release(p.A.is_squared() && p.A.rows() == p.c.size());
+  assert_release(p.c.size() == 2);
 
   auto a1 = p.A.col(0), a2 = p.A.col(1);
 
   if (a1.isZero() || a2.isZero())
-      draw_polyline({p.z-a1-a2,p.z+a1+a2}, style);
+      draw_polyline({p.c-a1-a2,p.c+a1+a2}, style);
   else
     draw_polygon({
-        p.z+a1+a2, p.z-a1+a2,
-        p.z-a1-a2, p.z+a1-a2
+        p.c+a1+a2, p.c-a1+a2,
+        p.c-a1-a2, p.c+a1-a2
       }, style);
 }
 
diff --git a/src/graphics/figures/codac2_Figure2D.h b/src/graphics/figures/codac2_Figure2D.h
index 9a950ea18..3b920c734 100644
--- a/src/graphics/figures/codac2_Figure2D.h
+++ b/src/graphics/figures/codac2_Figure2D.h
@@ -310,7 +310,7 @@ namespace codac2
       void draw_parallelepiped(const Parallelepiped& p, const StyleProperties& style = StyleProperties());
 
       /**
-       * \brief Draws a zonotope z+sum_i [-1,1] A_i on the figure
+       * \brief Draws a zonotope c+sum_i [-1,1] A_i on the figure
        * 
        * \param z Zonotope to draw (center and shape matrix)
        * \param style Style of the zonotope (edge color and fill color)
@@ -856,15 +856,15 @@ namespace codac2
       }
 
       /**
-       * \brief Draws a zonotope z+sum_i [-1,1] A_i on the figure
+       * \brief Draws a zonotope c+sum_i [-1,1] A_i on the figure
        * 
-       * \param z Zonotope to draw (center and shape matrix)
+       * \param c Zonotope to draw (center and shape matrix)
        * \param style Style of the zonotope (edge color and fill color)
        */
-      static void draw_zonotope(const Zonotope& z, const StyleProperties& style = StyleProperties())
+      static void draw_zonotope(const Zonotope& c, const StyleProperties& style = StyleProperties())
       {
         auto_init();
-        selected_fig()->draw_zonotope(z,style);
+        selected_fig()->draw_zonotope(c,style);
       }
 
       /**
diff --git a/src/graphics/figures/codac2_Figure3D.cpp b/src/graphics/figures/codac2_Figure3D.cpp
index 86d7fcdc0..ca0aee3ef 100644
--- a/src/graphics/figures/codac2_Figure3D.cpp
+++ b/src/graphics/figures/codac2_Figure3D.cpp
@@ -105,19 +105,19 @@ void Figure3D::draw_parallelogram(const Vector &c, const Matrix &A,
 
 void Figure3D::draw_parallelepiped(const Parallelepiped& p, const StyleProperties& style)
 {
-  assert_release(p.z.size() == 3);
+  assert_release(p.c.size() == 3);
   assert_release(p.A.rows() == 3 && p.A.cols() == 3);
 
   this->set_style_internal(style);
 
-  size_t ip0 = this->move_write_v(p.z,p.A,Vector({-1,-1,-1}));
-  size_t ip1 = this->move_write_v(p.z,p.A,Vector({-1,-1,1}));
-  size_t ip2 = this->move_write_v(p.z,p.A,Vector({-1,1,-1}));
-  size_t ip3 = this->move_write_v(p.z,p.A,Vector({-1,1,1}));
-  size_t ip4 = this->move_write_v(p.z,p.A,Vector({1,-1,-1}));
-  size_t ip5 = this->move_write_v(p.z,p.A,Vector({1,-1,1}));
-  size_t ip6 = this->move_write_v(p.z,p.A,Vector({1,1,-1}));
-  size_t ip7 = this->move_write_v(p.z,p.A,Vector({1,1,1}));
+  size_t ip0 = this->move_write_v(p.c,p.A,Vector({-1,-1,-1}));
+  size_t ip1 = this->move_write_v(p.c,p.A,Vector({-1,-1,1}));
+  size_t ip2 = this->move_write_v(p.c,p.A,Vector({-1,1,-1}));
+  size_t ip3 = this->move_write_v(p.c,p.A,Vector({-1,1,1}));
+  size_t ip4 = this->move_write_v(p.c,p.A,Vector({1,-1,-1}));
+  size_t ip5 = this->move_write_v(p.c,p.A,Vector({1,-1,1}));
+  size_t ip6 = this->move_write_v(p.c,p.A,Vector({1,1,-1}));
+  size_t ip7 = this->move_write_v(p.c,p.A,Vector({1,1,1}));
 
   _file << "f " << ip0 << " " << ip1 << " " << ip3 << " " << ip2 << "\n";
   _file << "f " << ip4 << " " << ip5 << " " << ip7 << " " << ip6 << "\n";
@@ -137,7 +137,7 @@ void Figure3D::draw_box(const IntervalVector& x, const StyleProperties& style)
 }
 
 void Figure3D::draw_zonotope(const Zonotope& z, const StyleProperties& style) {
-  assert_release(z.z.size() == 3);
+  assert_release(z.c.size() == 3);
    Matrix id = Matrix::Identity(3,3);
    this->set_style_internal(style);
    lock_style=true;
@@ -186,8 +186,8 @@ void Figure3D::draw_zonotope(const Zonotope& z, const StyleProperties& style) {
                   R1 -= Ak;
                }
           }
-          this->draw_parallelogram(z.z,id,R1+R2,Ai,Aj,style);
-          this->draw_parallelogram(z.z,id,-R1+R2,Ai,Aj,style);
+          this->draw_parallelogram(z.c,id,R1+R2,Ai,Aj,style);
+          this->draw_parallelogram(z.c,id,-R1+R2,Ai,Aj,style);
        }
     }
     lock_style=false;
@@ -214,10 +214,11 @@ void Figure3D::draw_arrow(const Vector& c, const Matrix &A,
 }
 
 
-void Figure3D::draw_axes(double size)
+void Figure3D::draw_axes(double size, const Vector& origin)
 {
+  assert_release(origin.size()==3);
   const std::string name="axes";
-  Vector z = Vector::zero(3);
+  Vector z = origin;
   // X axis
   Matrix AX = Matrix::Identity(3,3);
   draw_arrow(z,size*AX,StyleProperties(Color::red(),name));
diff --git a/src/graphics/figures/codac2_Figure3D.h b/src/graphics/figures/codac2_Figure3D.h
index 3887bdee1..442293832 100644
--- a/src/graphics/figures/codac2_Figure3D.h
+++ b/src/graphics/figures/codac2_Figure3D.h
@@ -116,7 +116,7 @@ namespace codac2
       void draw_parallelepiped(const Parallelepiped& p, const StyleProperties& style = { Color::dark_gray(0.5) });
 
       /**
-       * \brief Draws a zonotope z+sum_i [-1,1] A_i on the figure
+       * \brief Draws a zonotope c+sum_i [-1,1] A_i on the figure
        * 
        * \param z Zonotope to draw (center and shape matrix)
        * \param style Style of the zonotope (edge color)
@@ -146,8 +146,9 @@ namespace codac2
        * \brief Draws the (x,y,z) axes on the figure in red, green and blue
        * 
        * \param size Size of the axes
+       * \param origin Origin of the axes
        */
-      void draw_axes(double size = 1.0);
+      void draw_axes(double size = 1.0, const Vector& origin = Vector::Zero(3));
 
       /**
        * \brief Draws a parametric surface
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index c38934659..4ea53368d 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -54,8 +54,9 @@ list(APPEND SRC_TESTS # listing files without extension
   core/domains/interval/codac2_tests_IntervalMatrix
   core/domains/interval/codac2_tests_IntervalVector
   ../doc/manual/manual/intervals/src
-  core/domains/zonotope/codac2_tests_Parallelepiped
   core/domains/zonotope/codac2_tests_Parallelepiped_eval
+  core/domains/zonotope/codac2_tests_Parallelepiped
+  core/domains/zonotope/codac2_tests_Zonotope
   core/domains/tube/codac2_tests_TDomain
   core/domains/tube/codac2_tests_Slice
   core/domains/tube/codac2_tests_Slice_polygon
diff --git a/tests/core/domains/zonotope/codac2_tests_Parallelepiped.cpp b/tests/core/domains/zonotope/codac2_tests_Parallelepiped.cpp
index 2c5766d4b..2d203740b 100644
--- a/tests/core/domains/zonotope/codac2_tests_Parallelepiped.cpp
+++ b/tests/core/domains/zonotope/codac2_tests_Parallelepiped.cpp
@@ -26,7 +26,7 @@ TEST_CASE("Parallelepiped")
   CHECK((p.is_superset(IntervalVector({{0.,5.},{2.,7.},{4.,9.}})))==BoolInterval::UNKNOWN);
 
   Zonotope z = p.proj({2,1,0});
-  CHECK(z.z == Vector({4,2,0}));
+  CHECK(z.c == Vector({4,2,0}));
   CHECK(z.A == Matrix({{0.,1.,1.},{0.,1.,0.},{0.5,0.,0.}}));
   CHECK(z.box() == IntervalVector({{2.,6.},{1.,3.},{-0.5,0.5}}));
 }
diff --git a/tests/core/domains/zonotope/codac2_tests_Parallelepiped.py b/tests/core/domains/zonotope/codac2_tests_Parallelepiped.py
index 75b4cd987..c0eaa0a17 100644
--- a/tests/core/domains/zonotope/codac2_tests_Parallelepiped.py
+++ b/tests/core/domains/zonotope/codac2_tests_Parallelepiped.py
@@ -27,7 +27,7 @@ def test_parallelepiped(self):
     self.assertTrue((p.is_superset(IntervalVector([[0.,5.],[2.,7.],[4.,9.]])))==BoolInterval.UNKNOWN)
 
     z = p.proj([2,1,0])
-    self.assertTrue(z.z == Vector([4,2,0]))
+    self.assertTrue(z.c == Vector([4,2,0]))
     self.assertTrue(z.A == Matrix([[0,1,1],[0,1,0],[0.5,0,0]]))
     self.assertTrue(z.box() == IntervalVector([[2,6],[1,3],[-0.5,0.5]]))
       
diff --git a/tests/core/domains/zonotope/codac2_tests_Parallelepiped_eval.cpp b/tests/core/domains/zonotope/codac2_tests_Parallelepiped_eval.cpp
index 0ad038b38..9dd1705b2 100644
--- a/tests/core/domains/zonotope/codac2_tests_Parallelepiped_eval.cpp
+++ b/tests/core/domains/zonotope/codac2_tests_Parallelepiped_eval.cpp
@@ -28,17 +28,17 @@ TEST_CASE("Parallelepiped_eval")
   auto p1a = f1.parallelepiped_eval(Interval(-0.1,0.1));
   auto p1b = f1.parallelepiped_eval(1.0);
 
-  CHECK(Approx(p1a.z,1e-6) == Vector({0,0}));
+  CHECK(Approx(p1a.c,1e-6) == Vector({0,0}));
   CHECK(Approx(p1a.A,1e-6) == Matrix({{0.12,0},{0,0.02}}));
-  CHECK(Approx(p1b.z,1e-6) == Vector({1,1}));
+  CHECK(Approx(p1b.c,1e-6) == Vector({1,1}));
   CHECK(Approx(p1b.A,1e-6) == Matrix({{0,0},{0,0}}));
 
   auto pa = f2.parallelepiped_eval(Interval(-0.1,0.1), Interval(-0.1,0.1));
   auto pb = f2.parallelepiped_eval(1.0, Interval(-1,1));
 
-  CHECK(Approx(pa.z,1e-6) == Vector({0,0,0}));
+  CHECK(Approx(pa.c,1e-6) == Vector({0,0,0}));
   CHECK(Approx(pa.A,1e-6) == Matrix({{0.14,0,0},{0,0.14,0},{0,0,0.04}}));
-  CHECK(Approx(pb.z,1e-6) == Vector({1,0,1}));
+  CHECK(Approx(pb.c,1e-6) == Vector({1,0,1}));
   CHECK(Approx(pb.A,1e-5) == Matrix({{0.894428,0,1.78886},{0,3,0},{1.78886,0,-0.894427}}));
 
 
@@ -55,7 +55,7 @@ TEST_CASE("Parallelepiped_eval")
         auto p2 = f2.parallelepiped_eval(X0,Y0);
         auto p3 = f3.parallelepiped_eval(IntervalVector({X0,Y0}));
 
-        CHECK(Approx(p2.z,1e-6) == p3.z);
+        CHECK(Approx(p2.c,1e-6) == p3.c);
         CHECK(Approx(p2.A,1e-6) == p3.A);
         y0+=dx;
       }
diff --git a/tests/core/domains/zonotope/codac2_tests_Parallelepiped_eval.py b/tests/core/domains/zonotope/codac2_tests_Parallelepiped_eval.py
index c7dcd18ed..5cac5ffe7 100644
--- a/tests/core/domains/zonotope/codac2_tests_Parallelepiped_eval.py
+++ b/tests/core/domains/zonotope/codac2_tests_Parallelepiped_eval.py
@@ -27,17 +27,17 @@ def test_parallelepiped_eval(self):
     p1a = f1.parallelepiped_eval(Interval(-0.1,0.1))
     p1b = f1.parallelepiped_eval(1.0)
     
-    self.assertTrue(Approx(p1a.z,1e-6)==Vector([0.0,0.0]))
+    self.assertTrue(Approx(p1a.c,1e-6)==Vector([0.0,0.0]))
     self.assertTrue(Approx(p1a.A,1e-6)==Matrix([[0.12,0.0],[0.0,0.02]]))
-    self.assertTrue(Approx(p1b.z,1e-6)==Vector([1.0,1.0]))
+    self.assertTrue(Approx(p1b.c,1e-6)==Vector([1.0,1.0]))
     self.assertTrue(Approx(p1b.A,1e-6)==Matrix([[0.0,0.0],[0.0,0.0]]))
 
     pa = f2.parallelepiped_eval(Interval(-0.1,0.1), Interval(-0.1,0.1))
     pb = f2.parallelepiped_eval(1.0,Interval(-1,1))
 
-    self.assertTrue(Approx(pa.z,1e-6)==Vector([0,0,0]))
+    self.assertTrue(Approx(pa.c,1e-6)==Vector([0,0,0]))
     self.assertTrue(Approx(pa.A,1e-6)==Matrix([[0.14,0,0],[0,0.14,0],[0,0,0.04]]))
-    self.assertTrue(Approx(pb.z,1e-6)==Vector([1,0,1]))
+    self.assertTrue(Approx(pb.c,1e-6)==Vector([1,0,1]))
     self.assertTrue(Approx(pb.A,1e-5)==Matrix([[0.894428,0,1.78886],[0,3,0],[1.78886,0,-0.894427]]))
 
 
@@ -52,7 +52,7 @@ def test_parallelepiped_eval(self):
         p2 = f2.parallelepiped_eval(X0,Y0)
         p3 = f3.parallelepiped_eval(IntervalVector([X0,Y0]))
 
-        self.assertTrue(Approx(p2.z,1e-6)==p3.z)
+        self.assertTrue(Approx(p2.c,1e-6)==p3.c)
         self.assertTrue(Approx(p2.A,1e-6)==p3.A)
         y0 += dx
       x0 += dx
diff --git a/tests/core/domains/zonotope/codac2_tests_Zonotope.cpp b/tests/core/domains/zonotope/codac2_tests_Zonotope.cpp
new file mode 100644
index 000000000..60da5d7ea
--- /dev/null
+++ b/tests/core/domains/zonotope/codac2_tests_Zonotope.cpp
@@ -0,0 +1,28 @@
+/** 
+ *  Codac tests
+ * ----------------------------------------------------------------------------
+ *  \date       2025
+ *  \author     Maël Godard
+ *  \copyright  Copyright 2024 Codac Team
+ *  \license    GNU Lesser General Public License (LGPL)
+ */
+
+#include <catch2/catch_test_macros.hpp>
+#include <codac2_Zonotope.h>
+
+using namespace std;
+using namespace codac2;
+
+TEST_CASE("Zonotope")
+{
+  Zonotope Z1 (Vector({2,1}), Matrix({{0.2  ,0.08}, {0.04,0.18}}));
+  Zonotope Z2 (Vector({2,0.5}), Matrix({{-0.2}, {0.1}}));
+  auto Zs = Z1+Z2;
+
+  Vector c ({4,1.5});
+  Matrix A ({{0.2, 0.08, -0.2},
+              {0.04, 0.18, 0.1}});
+  CHECK(Zs.c == c);
+  CHECK(Zs.A == A);
+}
+
diff --git a/tests/core/domains/zonotope/codac2_tests_Zonotope.py b/tests/core/domains/zonotope/codac2_tests_Zonotope.py
new file mode 100644
index 000000000..46ddd969a
--- /dev/null
+++ b/tests/core/domains/zonotope/codac2_tests_Zonotope.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+
+#  Codac tests
+# ----------------------------------------------------------------------------
+#  \date       2025
+#  \author     Maël Godard
+#  \copyright  Copyright 2024 Codac Team
+#  \license    GNU Lesser General Public License (LGPL)
+
+import unittest
+from codac import *
+import sys
+import math
+
+class TestZonotope(unittest.TestCase):
+
+  def test_zonotope(self):
+
+    Z1 = Zonotope(Vector([2,1]), Matrix([[0.2  ,0.08], [0.04,0.18]]))
+    Z2 = Zonotope(Vector([2,0.5]), Matrix([[-0.2], [0.1]]))
+    Zs = Z1+Z2
+
+    c = Vector([4,1.5])
+    A = Matrix([[0.2  ,0.08, -0.2],
+                [0.04, 0.18, 0.1]])
+    self.assertTrue(Zs.c == c)
+    self.assertTrue(Zs.A == A)
+      
+if __name__ ==  '__main__':
+  unittest.main()
\ No newline at end of file
diff --git a/tests/core/peibos/codac2_tests_peibos.cpp b/tests/core/peibos/codac2_tests_peibos.cpp
index bda717048..755b741e7 100644
--- a/tests/core/peibos/codac2_tests_peibos.cpp
+++ b/tests/core/peibos/codac2_tests_peibos.cpp
@@ -69,12 +69,12 @@ TEST_CASE("Peibos")
 
   CHECK(v_par_3d.size() == 6);
 
-  CHECK(Approx(v_par_3d[0].z,1e-6) == Vector({1.,0.,0.})); 
-  CHECK(Approx(v_par_3d[1].z,1e-6) == Vector({0.,1.,0.}));
-  CHECK(Approx(v_par_3d[2].z,1e-6) == Vector({-1.,0.,0.}));
-  CHECK(Approx(v_par_3d[3].z,1e-6) == Vector({0.,-1.,0.}));
-  CHECK(Approx(v_par_3d[4].z,1e-6) == Vector({0.,0.,-1.}));
-  CHECK(Approx(v_par_3d[5].z,1e-6) == Vector({0.,0.,1.}));
+  CHECK(Approx(v_par_3d[0].c,1e-6) == Vector({1.,0.,0.})); 
+  CHECK(Approx(v_par_3d[1].c,1e-6) == Vector({0.,1.,0.}));
+  CHECK(Approx(v_par_3d[2].c,1e-6) == Vector({-1.,0.,0.}));
+  CHECK(Approx(v_par_3d[3].c,1e-6) == Vector({0.,-1.,0.}));
+  CHECK(Approx(v_par_3d[4].c,1e-6) == Vector({0.,0.,-1.}));
+  CHECK(Approx(v_par_3d[5].c,1e-6) == Vector({0.,0.,1.}));
 
   double a = 4.35066;
 
diff --git a/tests/core/peibos/codac2_tests_peibos.py b/tests/core/peibos/codac2_tests_peibos.py
index 66042d8e0..f4f12191e 100644
--- a/tests/core/peibos/codac2_tests_peibos.py
+++ b/tests/core/peibos/codac2_tests_peibos.py
@@ -63,12 +63,12 @@ def test_peibos(self):
 
     self.assertTrue(len(v_par_3d) == 6)
 
-    self.assertTrue(Approx(v_par_3d[0].z,1e-6) == Vector([1.,0.,0.]))
-    self.assertTrue(Approx(v_par_3d[1].z,1e-6) == Vector([0.,1.,0.]))
-    self.assertTrue(Approx(v_par_3d[2].z,1e-6) == Vector([-1,0.,0.]))
-    self.assertTrue(Approx(v_par_3d[3].z,1e-6) == Vector([0.,-1.,0.]))
-    self.assertTrue(Approx(v_par_3d[4].z,1e-6) == Vector([0.,0.,-1.]))
-    self.assertTrue(Approx(v_par_3d[5].z,1e-6) == Vector([0.,0.,1.]))
+    self.assertTrue(Approx(v_par_3d[0].c,1e-6) == Vector([1.,0.,0.]))
+    self.assertTrue(Approx(v_par_3d[1].c,1e-6) == Vector([0.,1.,0.]))
+    self.assertTrue(Approx(v_par_3d[2].c,1e-6) == Vector([-1,0.,0.]))
+    self.assertTrue(Approx(v_par_3d[3].c,1e-6) == Vector([0.,-1.,0.]))
+    self.assertTrue(Approx(v_par_3d[4].c,1e-6) == Vector([0.,0.,-1.]))
+    self.assertTrue(Approx(v_par_3d[5].c,1e-6) == Vector([0.,0.,1.]))
 
     a = 4.35066