You can give it a Periodic Time Event, in which it will constantly repeat until it's turned off. Basically, just have another trigger turn it on, and then, when it's done, turn it off. You can also use for loops if you know how long you'll want the loop to repeat itself. I think WC3 also has while loops, but I haven't been doing WC3 triggering for awhile (but, I have 5 years xp in Java, 3 years xp in C++, and 3 year xp in VB).