diff --git a/src/index.ts b/src/index.ts
index abc73a1..7f4e1f8 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -31,7 +31,7 @@ function get_functions(time: number = thisLayer.time)
 	// https://gist.github.com/animoplex/aafd6a157282351c8dfeea385d969ef2
 	function inertial_bounce(amp: number, freq: number, decay: number, input_property = thisProperty)
 	{
-		const n = get_key_index();
+		const n = get_key_index(undefined, input_property);
 		let t = 0;
 
 		if (n != 0)