How do I start new rows automatically

Here, rather simple code. Though you haven't answered me whether you want both bX and bY or just bY. So I will just show you for both bX and bY. As for only bY, I could not figure out what you really want me to put for bX but you can use this code to infer if you only need bY or you can explain to me more because I believe you need both bX and bY to be dynamic. Otherwise, I need more explanation.

In the previous question I didn't notice you are using AS2. So I changed the datatype to Number, I wondered how you got int to compile in AS2?

Example 1:

for (var i:Number = 0; i < maskArray.length; i++) {
    maskBlock(maskArray[i], qmaskW, qmaskH, qmaskW * ((maskArray[i] - 1) % 4), qmaskH * (maskArray[i] - 1 / 4 >> 0));
}

If you do not understand any part of this code, feel free to ask.

It works just perfect. Thakns a lot