diff --git a/examples/plotter/__init__.py b/examples/plotter/__init__.py
index b7720f9..4bb072b 100644
--- a/examples/plotter/__init__.py
+++ b/examples/plotter/__init__.py
@@ -116,13 +116,13 @@ class Plotter(MoveHub):
 
     def circle(self, radius):
         if not self.is_tool_down:
-           self._tool_down()
+            self._tool_down()
 
         parts = int(2 * math.pi * radius * 5)
         dur = 0.225
         logging.info("Circle of radius %s, %s parts with %s time", radius, parts, dur)
         for x in range(0, parts):
-            speed_a = math.sin(x * 2 * math.pi / parts)
-            speed_b = math.cos(x * 2 * math.pi / parts)
+            speed_a = math.sin(x * 2.0 * math.pi / float(parts))
+            speed_b = math.cos(x * 2.0 * math.pi / float(parts))
             logging.debug("A: %s, B: %s", speed_a, speed_b)
             self.motor_AB.timed(dur, speed_a * BASE_SPEED, -speed_b * BASE_SPEED * MOTOR_RATIO)
diff --git a/examples/plotter/try.py b/examples/plotter/try.py
index 6528453..406453b 100644
--- a/examples/plotter/try.py
+++ b/examples/plotter/try.py
@@ -42,6 +42,23 @@ def romb():
     plotter.line(-FIELD_WIDTH, FIELD_WIDTH * 2)
 
 
+def circles():
+    plotter.move(FIELD_WIDTH / 5.0, 0)
+    plotter.circle(FIELD_WIDTH / 5.0)
+
+    plotter.move(FIELD_WIDTH / 5.0, 0)
+    plotter.circle(FIELD_WIDTH / 4.0)
+
+    plotter.move(FIELD_WIDTH / 5.0, 0)
+    plotter.circle(FIELD_WIDTH / 3.0)
+
+    plotter.move(FIELD_WIDTH / 5.0, 0)
+    plotter.circle(FIELD_WIDTH / 2.0)
+
+    plotter.move(FIELD_WIDTH / 5.0, 0)
+    plotter.circle(FIELD_WIDTH / 1.0)
+
+
 if __name__ == '__main__':
     logging.basicConfig(level=logging.INFO)
 
@@ -61,11 +78,7 @@ if __name__ == '__main__':
         # square()
         # cross()
         # romb()
-        plotter.move(FIELD_WIDTH / 2.0, 0)
-        plotter.circle(FIELD_WIDTH / 2.0)
-
-        plotter.move(FIELD_WIDTH / 2.0, 0)
-        plotter.circle(FIELD_WIDTH)
+        circles()
         pass
     finally:
         plotter.finalize()