diff --git a/Angle.cpp b/Angle.cpp
index 5b71d0d..00ea7cb 100644
--- a/Angle.cpp
+++ b/Angle.cpp
@@ -76,9 +76,8 @@ AngleOf<signed short> AngleOf<signed short>::Degrees(float angle) {
 
 template <>
 AngleOf<signed short> AngleOf<signed short>::Radians(float angle) {
-  if (!isfinite(angle)) {
+  if (!isfinite(angle))
     return AngleOf<signed short>(0);
-  }
 
   // map float [-PI..PI) to integer [-32768..32767]
   signed short value = (signed short)(angle / pi * 32768.0F);
@@ -130,6 +129,13 @@ float AngleOf<signed char>::InRadians() const {
 
 //===== Generic
 
+template <typename T>
+const AngleOf<T> AngleOf<T>::zero = AngleOf<T>();
+template <typename T>
+const AngleOf<T> AngleOf<T>::deg90 = AngleOf<T>::Degrees(90);
+template <typename T>
+const AngleOf<T> AngleOf<T>::deg180 = AngleOf<T>::Degrees(180);
+
 template <typename T>
 bool AngleOf<T>::operator==(const AngleOf<T> a) const {
   return this->value == a.value;
@@ -267,6 +273,11 @@ AngleOf<T> AngleOf<T>::Atan(float f) {
   return AngleOf<T>::Radians(atanf(f));
 }
 
+template <typename T>
+AngleOf<T> Passer::LinearAlgebra::AngleOf<T>::Atan2(float f1, float f2) {
+  return AngleOf<T>::Radians(atan2f(f1, f2));
+}
+
 // template <>
 // float AngleOf<float>::CosineRuleSide(float a, float b, AngleOf<float> gamma)
 // {
diff --git a/Angle.h b/Angle.h
index 59ba151..384c66f 100644
--- a/Angle.h
+++ b/Angle.h
@@ -21,6 +21,10 @@ class AngleOf {
   static AngleOf<T> Degrees(float f);
   static AngleOf<T> Radians(float f);
 
+  const static AngleOf<T> zero;
+  const static AngleOf<T> deg90;
+  const static AngleOf<T> deg180;
+
   float InDegrees() const;
   float InRadians() const;
 
@@ -64,6 +68,7 @@ class AngleOf {
   static AngleOf<T> Acos(float f);
   static AngleOf<T> Asin(float f);
   static AngleOf<T> Atan(float f);
+  static AngleOf<T> Atan2(float f1, float f2);
 
   static float CosineRuleSide(float a, float b, AngleOf<T> gamma);
   static AngleOf<T> CosineRuleAngle(float a, float b, float c);
diff --git a/Direction.cpp b/Direction.cpp
index 8dc6bad..e4a26f9 100644
--- a/Direction.cpp
+++ b/Direction.cpp
@@ -24,8 +24,13 @@ DirectionOf<T>::DirectionOf(AngleOf<T> horizontal, AngleOf<T> vertical) {
 
 template <typename T>
 DirectionOf<T>::DirectionOf(Vector3 v) {
-  this->horizontal = AngleOf<T>::Radians(atan2f(v.Right(), v.Forward()));
-  this->vertical = AngleOf<T>::Radians(-(0.5f * pi) - acosf(v.Up()));
+  this->horizontal = AngleOf<T>::Atan2(
+      v.Right(),
+      v.Forward());  // AngleOf<T>::Radians(atan2f(v.Right(), v.Forward()));
+  this->vertical =
+      -AngleOf<T>::deg90 -
+      AngleOf<T>::Acos(
+          v.Up());  // AngleOf<T>::Radians(-(0.5f * pi) - acosf(v.Up()));
   Normalize();
 }
 
@@ -34,19 +39,19 @@ const DirectionOf<T> DirectionOf<T>::forward =
     DirectionOf<T>(AngleOf<T>(), AngleOf<T>());
 template <typename T>
 const DirectionOf<T> DirectionOf<T>::back =
-    DirectionOf<T>(AngleOf<T>::Degrees(180), AngleOf<T>());
+    DirectionOf<T>(AngleOf<T>::deg180, AngleOf<T>());
 template <typename T>
 const DirectionOf<T> DirectionOf<T>::up =
-    DirectionOf<T>(AngleOf<T>(), AngleOf<T>::Degrees(90));
+    DirectionOf<T>(AngleOf<T>(), AngleOf<T>::deg90);
 template <typename T>
 const DirectionOf<T> DirectionOf<T>::down =
-    DirectionOf<T>(AngleOf<T>(), AngleOf<T>::Degrees(-90));
+    DirectionOf<T>(AngleOf<T>(), -AngleOf<T>::deg90);
 template <typename T>
 const DirectionOf<T> DirectionOf<T>::left =
-    DirectionOf<T>(AngleOf<T>::Degrees(-90), AngleOf<T>());
+    DirectionOf<T>(-AngleOf<T>::deg90, AngleOf<T>());
 template <typename T>
 const DirectionOf<T> DirectionOf<T>::right =
-    DirectionOf<T>(AngleOf<T>::Degrees(90), AngleOf<T>());
+    DirectionOf<T>(AngleOf<T>::deg90, AngleOf<T>());
 
 template <typename T>
 DirectionOf<T> Passer::LinearAlgebra::DirectionOf<T>::Degrees(float horizontal,
@@ -70,14 +75,14 @@ bool Passer::LinearAlgebra::DirectionOf<T>::operator==(
 
 template <typename T>
 DirectionOf<T> Passer::LinearAlgebra::DirectionOf<T>::operator-() const {
-  DirectionOf<T> r = DirectionOf<T>(this->horizontal + AngleOf<T>::Degrees(180),
-                                    -this->vertical);
+  DirectionOf<T> r =
+      DirectionOf<T>(this->horizontal + AngleOf<T>::deg180, -this->vertical);
   return r;
 }
 
 template <typename T>
 Vector3 DirectionOf<T>::ToVector3() {
-  Vector3 v = Quaternion::Euler(-(this->vertical.InDegrees()),
+  Vector3 v = Quaternion::Euler(-this->vertical.InDegrees(),
                                 this->horizontal.InDegrees(), 0) *
               Vector3::forward;
   return v;
@@ -85,10 +90,10 @@ Vector3 DirectionOf<T>::ToVector3() {
 
 template <typename T>
 void DirectionOf<T>::Normalize() {
-  if (this->vertical > AngleOf<T>::Degrees(90) ||
-      this->vertical < AngleOf<T>::Degrees(-90)) {
-    this->horizontal += AngleOf<T>::Degrees(180);
-    this->vertical = AngleOf<T>::Degrees(180) - this->vertical;
+  if (this->vertical > AngleOf<T>::deg90 ||
+      this->vertical < -AngleOf<T>::deg90) {
+    this->horizontal += AngleOf<T>::deg180;
+    this->vertical = AngleOf<T>::deg180 - this->vertical;
   }
 }
 
diff --git a/SwingTwist.cpp b/SwingTwist.cpp
index a82097c..4d9fc1f 100644
--- a/SwingTwist.cpp
+++ b/SwingTwist.cpp
@@ -31,8 +31,7 @@ template <typename T>
 SwingTwistOf<T> SwingTwistOf<T>::Degrees(float horizontal,
                                          float vertical,
                                          float twist) {
-  DirectionOf<T> swing = DirectionOf<T>(AngleOf<T>::Degrees(horizontal),
-                                        AngleOf<T>::Degrees(vertical));
+  DirectionOf<T> swing = DirectionOf<T>::Degrees(horizontal, vertical);
   AngleOf<T> twistAngle = AngleOf<T>::Degrees(twist);
   SwingTwistOf<T> orientation = SwingTwistOf(swing, twistAngle);
   return orientation;
@@ -50,9 +49,8 @@ template <typename T>
 SwingTwistOf<T> Passer::LinearAlgebra::SwingTwistOf<T>::FromQuaternion(
     Quaternion q) {
   Vector3 angles = Quaternion::ToAngles(q);
-  SwingTwistOf<T> r = SwingTwistOf<T>(AngleOf<T>::Degrees(angles.Up()),
-                                      AngleOf<T>::Degrees(angles.Right()),
-                                      AngleOf<T>::Degrees(angles.Forward()));
+  SwingTwistOf<T> r =
+      SwingTwistOf<T>::Degrees(angles.Up(), angles.Right(), angles.Forward());
 
   return r;
 }