diff --git a/y2019/joystick_angle.h b/y2019/joystick_angle.h
index a2c7e36..09ab8af 100644
--- a/y2019/joystick_angle.h
+++ b/y2019/joystick_angle.h
@@ -9,12 +9,7 @@
 namespace y2019 {
 namespace input {
 namespace joysticks {
-namespace {
-constexpr double kJoystickLeft = -0.5;
-constexpr double kJoystickRight = 0.5;
-constexpr double kJoystickUp = 0.5;
-constexpr double kJoystickDown = -0.5;
-}
+bool AngleCloseTo(double angle, double near, double range);
 
 enum class JoystickAngle {
   kDefault,