diff --git a/prototype/circles.py b/prototype/circles.py
index 8159d15..9ca6600 100644
--- a/prototype/circles.py
+++ b/prototype/circles.py
@@ -3,6 +3,9 @@ import matplotlib.pyplot as plt
 import math
 import operator
 
+# scale in inkscape
+# 1 unit = 0.283 mm
+scale = 1000.0/282.222
 
 def svg_circle(id, name, c, r):
     # create circle object in svg notation
@@ -16,6 +19,40 @@ def svg_circle(id, name, c, r):
 
     return text
 
+def svg_half_circle(id, name, c, r, angle):
+    # draws half a circle centered at c with radius r
+    # angle specifies how the half circle should be rotated
+    # for the default angle of zero, it draws the top half of the circle
+
+    # convert angle to radians
+    angle = angle/360.0 * 2.0 * np.pi
+
+    # compute starting point
+    v = np.array([np.cos(angle), np.sin(angle)])
+    begin = c + r * v   # in millimeters
+    begin *= scale      # in pixel units
+
+    # compute end point
+    end = c - r * v     # in millimeters
+    end *= scale        # in pixel units
+
+    radius_scaled = r * scale
+
+    text = ['   <g id="mygroup">\n '
+            '      <path \n     '
+            '        id="path666" \n       '
+            '        style="fill:none;stroke:#ff0000;stroke-width:0.60000002" \n'
+            '        d="M {} {} A {} {} {} 1 1 {} {}"'
+            '      />\n'
+            '     <path \n'
+            '       id="path667" \n'
+            '       style="fill:none;stroke:#ff0000;stroke-width:0.60000002"\n '
+            '       d="M 0 0 L 1000 1000"'
+            '       />\n'
+            '   </g>\n'.format(begin[0], begin[1], radius_scaled, radius_scaled, 0, end[0], end[1])]
+
+    return text
+
 
 def svg_rectangle(id, name, c, width, heigth, angle):
     x = np.sqrt(c[0]**2 + c[1]**2) - width/2
@@ -194,7 +231,7 @@ class PlateLayout:
         # compute coordinates and various measurements for fixed radii of plate and tubes
         self.target_plate_radius = 160.0
         self.target_center_hole_radius = 7.5
-        self.target_radius_1 = 50.2
+        self.target_radius_1 = 50.5
         self.target_radius_2 = 20.0
         teeth = 200
 
@@ -430,20 +467,28 @@ class PlateLayout:
         text = svg_circle(0, 'plate', (0,0), self.target_plate_radius)
         f_lines = f_lines + text
 
+        output_all = False
+        if output_all:
+            N = len(self.tube_1_coords.items())
+        else:
+            N = 1
+
         # output big circles as svg
-        for k, c in self.tube_1_coords.items():
-            text = svg_circle(k, 'big circle', c, self.target_radius_1)
+        for k, c in self.tube_1_coords.items()[0:N]:
+            #text = svg_circle(k, 'big circle', c, self.target_radius_1)
+            angle = self.tube_1_angles[k]
+            text = svg_half_circle(k, 'big circle', c, self.target_radius_1, angle)
             f_lines = f_lines + text
             pass
 
         # output small circles as svg
-        for k, c in self.tube_2_coords.items():
+        for k, c in self.tube_2_coords.items()[0:N]:
             text = svg_circle(k, 'small circle', c, self.target_radius_2)
             f_lines = f_lines + text
             pass
 
         # gear markings for big cirlces and small circles
-        for k, c in self.tube_1_tangents.items():
+        for k, c in self.tube_1_tangents.items()[0:N]:
             circle_midpoint = self.tube_1_coords[k]
             v = np.array(c[0]) - np.array(circle_midpoint)
             v = v/np.linalg.norm(v)
@@ -457,7 +502,7 @@ class PlateLayout:
             f_lines = f_lines + text
             pass
 
-        for k, c in self.tube_2_tangents.items():
+        for k, c in self.tube_2_tangents.items()[0:N]:
             circle_midpoint = self.tube_2_coords[k]
             v = np.array(c[0]) - np.array(circle_midpoint)
             v = v/np.linalg.norm(v)
@@ -472,19 +517,19 @@ class PlateLayout:
             pass
 
         # output cuts for big circles
-        for k, c in self.tube_1_cuts.items():
+        for k, c in self.tube_1_cuts.items()[0:N]:
             text = svg_rectangle(k, 'cut', c['center'], c['length'], c['width'], c['angle_deg'])
             f_lines = f_lines + text
             pass
 
         # output cuts for small circles
-        for k, c in self.tube_2_cuts.items():
+        for k, c in self.tube_2_cuts.items()[0:N]:
             text = svg_rectangle(k, 'cut', c['center'], c['length'], c['width'], c['angle_deg'])
             f_lines = f_lines + text
             pass
 
         # lines for manufacturing out of multiple pieces
-        for k, a in self.tube_1_angles.items():
+        for k, a in self.tube_1_angles.items()[0:N]:
             a = a/360.0 * 2.0 * np.pi
             r1 = np.linalg.norm(np.array(self.tube_1_coords[k])) - self.target_radius_1
             vunit = np.array([np.cos(a), np.sin(a)])