Random Clip Instances

I have a row of blinking clip instances on the root timeline which I’m trying to play at random intervals. I have thirteen clips, named blink_1, blink_2, and so on. I placed the function below on the root timeline to play the clips, but it’s not working. Can anyone see something I’m missing?

function blink() {
var i = Math.round(Math.random()*200);
if (i<5) {
ii = Math.round(Math.random()*13);
var clipNum = String(ii);
var thisClip = String(“blink_”+clipNum);