--- a/kubik.py	Mon Jul 07 21:30:33 2014 +0000
+++ b/kubik.py	Tue Jul 08 20:02:35 2014 +0000
@@ -59,7 +59,8 @@
     # Lengths of leg segments, in mm
     coxa = 12.5  # between the hip and the knee
     femur = 30.0  # between the knee and the ankle
-    tibia = 35.0  # between the ankle and the foot
+    tibia = 36.0  # between the ankle and the foot
+    base = 45.0, 45.0  # from the center of body
 
     def __init__(self, hip, knee, ankle, hip_offset=0):
         self.hip = hip
@@ -96,6 +97,15 @@
                 position[i] = self.position[i]
         self.position = position
 
+    def rotate(self, degrees):
+        """Rotate the leg around the center of the body horizontally."""
+        x, y, z = self.position
+        bx, by = self.base[0] + x, self.base[1] + y
+        r = _length(bx, by)
+        x = r * math.cos(math.radians(degrees)) - self.base[0]
+        y = r * math.sin(math.radians(degrees)) - self.base[1]
+        self.move_to((x, y, None))
+
     def update(self):
         hip, knee, ankle = self._inverse_kinematics(self.position)
         self.hip.move_degrees(hip)