DYO: Advance/Decline Line

Question:

I have been trying to make a proper cumulative advance/decline line with $ADD and "design your own".  It should be quite simple shouldn't it -just adding the close to the previous days close but how do you set a day to start from?

Answer:

Try this:

When first applied to a chart, the accumulator variable [250] will be zero, and this is where each close is summed and resaved by Line A, from first bar in file through current bar in file.  Have Close Only checked.