diff --git a/main.py b/main.py
index 6915220..4227684 100644
--- a/main.py
+++ b/main.py
@@ -286,8 +286,8 @@ block_list = ["blue_concrete", "red_concrete", "green_concrete",
 # p = Polyline((Point2D(-1225, 468), Point2D(-1138, 481),
 #              Point2D(-1188, 451), Point2D(-1176, 409), Point2D(-1179, 399)))
 
-p = Polyline((Point2D(32, 0), Point2D(16, 16),
-             Point2D(16, 0), Point2D(0, 0)))
+p = Polyline((Point2D(64, -20), Point2D(48, 32),
+             Point2D(16, 0), Point2D(0, 0), Point2D(-10, -10)))
 
 # Point2D(-1156, 378), Point2D(-1220, 359), Point2D(-1265, 290)
 # print(p.alpha_radii)
diff --git a/networks/geometry/Polyline.py b/networks/geometry/Polyline.py
index 9da658b..5cca24b 100644
--- a/networks/geometry/Polyline.py
+++ b/networks/geometry/Polyline.py
@@ -26,7 +26,7 @@ class Polyline:
             raise ValueError("The list must contain at least 4 elements.")
 
         self.vectors = [None] * self.length_polyline  # v
-        self.lengths = [None] * self.length_polyline  # l
+        self.lengths = [None] * (self.length_polyline - 1)  # l
         self.unit_vectors = [None] * self.length_polyline  # n
         self.tangente = [0] * self.length_polyline  # f
 
@@ -45,7 +45,7 @@ class Polyline:
 
     def get_radii(self):
         for i in range(1, self.length_polyline-1):
-            print(self.alpha_radii[i] * self.tangente[i],
+            print("\nalpha_radii, tan", self.alpha_radii[i] * self.tangente[i],
                   self.alpha_radii[i], self.tangente[i])
             self.radii[i] = round(self.alpha_radii[i] * self.tangente[i])
         return self.radii
@@ -53,10 +53,11 @@ class Polyline:
     def get_centers(self):
         for i in range(1, self.length_polyline-1):
             bisector = (self.unit_vectors[i] - self.unit_vectors[i-1]) / (
-                np.linalg.norm(self.unit_vectors[i] + self.unit_vectors[i-1]))
+                np.linalg.norm(self.unit_vectors[i] - self.unit_vectors[i-1]))
+            print("bi", bisector)
 
-            array = self.points[i] + sqrt(self.radii[i]
-                                          ** 2 + self.alpha_radii[i] ** 2) * bisector
+            array = self.points[i] + sqrt((self.radii[i]
+                                          ** 2) + (self.alpha_radii[i] ** 2)) * bisector
             self.centers[i] = Point2D(array[0], array[1]).round()
         return self.centers
 
@@ -124,7 +125,7 @@ class Polyline:
 
         # Between two segments, there is only one angle
         for k in range(1, self.length_polyline-1):
-            dot = np.dot(self.unit_vectors[k], -self.unit_vectors[k-1])
+            dot = np.dot(self.unit_vectors[k], self.unit_vectors[k-1])
             self.tangente[k] = sqrt((1+dot)/(1-dot))
 
     def _compute_alpha_radii(self):
diff --git a/output_image.png b/output_image.png
index 2e233fb..ea39389 100644
Binary files a/output_image.png and b/output_image.png differ