diff --git a/src/ex.rs b/src/ex.rs
index ebfd1e0..601198c 100644
--- a/src/ex.rs
+++ b/src/ex.rs
@@ -149,9 +149,10 @@ pub fn spiral(k: u32) -> impl Fn(f64) -> [f64; 2] {
 }
 
 pub fn spiral_1d(k: u32) -> impl Fn(f64) -> [f64; 2] {
-    let x2pi = (k as f64) * core::f64::consts::TAU;
+    let k = k as f64;
+    let x2pi = k * core::f64::consts::TAU;
     move |t: f64| {
-        let ttcos = (t * core::f64::consts::TAU).cos();
+        let ttcos = k * (t * core::f64::consts::TAU).cos();
         let ttxsin = (t * x2pi).sin();
         [ttcos, ttxsin]
     }