Points such as the ASC or MC can receive aspects but can't cast them. Aspect theory was based on the idea of receiving and reflecting light (the word aspect means to view (in the sense of see). We can go outside at night and see the Moon or Venus or any of the other classical seven. The reason why we can see them is that they reflect light.
The Ascendant or MC may (and most likely are) simply empty space, it's the piece of empty space that's either rising or culminating (respectively) at that moment but it's not viewable. You can't look up and say, 'Oh look there's the midheaven' in a meaningful way.
So I'd go along with Beth Anne, that the only time they can form part of a pattern is when there's a planet that is conjunct them. Then you can see them or at least a 'flag' of where they are. But don't neglect aspects received. An Ascendant which is trined by Jupiter is differently affected than an Ascendant that is squared by Mars There is no effect on Jupiter or Mars in either case, which is why they don't affect a pattern involving Jupiter or Mars
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I'm not a fan of the idea of aspect patterns as having meaning that is independent of the aspects that comprise them, mainly because that suggests that the pattern is what is important, not the planets that comprise it. To me the quality of the planets is at least, if not more important in interpreting aspects than the nature of the aspect itself.