1 files changed, 12 insertions, 1 deletions
diff --git a/color.py b/color.py
index 058abb4..c65252b 100644
--- a/color.py
+++ b/color.py
@@ -7,7 +7,7 @@ class Vector(object):
     __slots__ = ('x', 'y', 'z')
 
     """3-dimensional vector class."""
-    def __init__(self, x, y, z):
+    def __init__(self, x=0, y=0, z=0):
         """Create a vector from its components."""
         self.x = x
         self.y = y
@@ -40,6 +40,17 @@ class Vector(object):
     def __eq__(self, other):
         return self.x == other.x and self.y == other.y and self.z == other.z
 
+    def unit(self):
+        return self / abs(self)
+
+    def rot2d(self, theta):
+        costheta = math.cos(theta)
+        sintheta = math.sin(theta)
+        new_x = self.x * costheta - self.y * sintheta
+        new_y = self.x * sintheta + self.y * costheta
+        return self.__class__(new_x, new_y)
+
+
     @property
     def components(self):
         return (self.x, self.y, self.z)