pub fn len_values_sq<T>(x: &T, y: &T, z: &T) -> Twhere T: Add<T, Output = T>, for<'a, 'b> &'a T: Mul<&'b T, Output = T>,
assert_eq!(vec3::len_values_sq(&1_f32, &1_f32, &1_f32), 3_f32);