Hello, Community! A problem: there is a list (counted before, not to be count in parallel with next step), now it's a base for next step of computation. I need to take one element of a list (its place is important) and use it to compute a sublist of the first list. Then exclude this sublist from the first list, and take new element (of a new shorter list), compute new sublist... Repeate a loop till the first list becomes {}. If a loop counter is a number - all is OK: increments ++,-- work good. But when i try list as a loop counter and decrease it by Complement - have a problem. First i did it by hands - in one notebook count sublist, in second - exclude it from first list, take this result to the first notebook and so on. Example - see attached file