Movement data display in Graph and Steps Counter

I think you're seeing l=!l and thinking it's the number one, not the letter l?

If you want them all to blink the same, it's best just to use the single variable l and call digitalWrite 3 times:

var l;setInterval("l=!l;digitalWrite(LED1,l)­;digitalWrite(LED2,l);digitalWrite(LED3,­l);",200);