diff --git a/src/lib.rs b/src/lib.rs
index e2bb071..13e9be9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -25,7 +25,7 @@ pub fn disable_mouse_trap(mut windows: ResMut<Windows>) {
     window.set_cursor_visibility(true);
 }
 
-pub fn random_sphere_vec(r: &mut impl rand::prelude::Rng) -> Vec3 {
+pub fn random_unit_vec(r: &mut impl rand::prelude::Rng) -> Vec3 {
     // https://mathworld.wolfram.com/SpherePointPicking.html
     // Marsaglia (1972) for picking x1 and x2 from (-1, 1) and generating surface
     // points directly if their sum is less than 1.
@@ -38,7 +38,7 @@ pub fn random_sphere_vec(r: &mut impl rand::prelude::Rng) -> Vec3 {
         x2 = r.gen_range(-1.0..=1.0);
         ssum = x1.powi(2) + x2.powi(2);
     }
-    let sqrt = (1.0 - x1.powi(2) - x2.powi(2)).sqrt();
+    let sqrt = (1.0 - ssum).sqrt();
     let x = 2.0 * x1 * sqrt;
     let y = 2.0 * x2 * sqrt;
     let z = 1.0 - 2.0 * ssum;
diff --git a/src/lights.rs b/src/lights.rs
index f6001e7..216d0a4 100644
--- a/src/lights.rs
+++ b/src/lights.rs
@@ -25,7 +25,7 @@ fn spawn_moving_lights(
     // spawn 200 orbiting bisexual lights
     for _ in 0..255 {
         // mechanics
-        let axis = crate::random_sphere_vec(rng);
+        let axis = crate::random_unit_vec(rng);
         let angle = rng.gen_range(0.0..TAU);
         let rate: f32 = rng.gen_range(7.0..10.0);
         let rate = rate.to_radians();