How do I create a nested loop with condition?

It's not really important. I am not good at english and there are risks that I was misunderstood. But the main thing is that the problem is solved. There are maybe better solutions. I don't know

It nests the loops. Two loops in one event is the same as having one loop and then another loop in a subevent under that.

Ahh, thanks for the clarification ASHLEY. As a side note then, maybe there should be a clause regarding this in the manual. This specific case is a little ambiguous. Going off of how actions and events are written to work in the manual, and understanding how loops work, I interpreted it as both loops running together. It would make more sense conceptually in the visual editor if to have a nested loop one of the loops needed to be added as a subevent.

located at tutorials/ 1339/ calculating-rectangular-coverage-area

you could do it like this as well

Have read now. Very interresting demos and tutorial. Thanks!