Easiest way to loop it would be making it circular. OK, jokes aside, moving along ticking x pixels each second is easy: start value+[s]*x (maybe you will need to change the sign to negative for your direction). Once [s] is used there should appear a check box for sweeping effect. I am not sure how it works now in 2.0, but to make it sweeping continuously would probably need two such strips in same place. One would cover the area while the other is sweeping back to start. Look in this thread, maybe you get some idea: