Shape or shapes ? , cause أشكال means several Shapes , and شكل mean one shape i think it's أشكال الفتاة الآلية = Shapes of a robot girl but if you want to say (shape of the backside of girls ) then = الشكل الخلفي للفتيات

It doesn't make any sense to me. I think there is something wrong with your typing or spelling or dictation. You need to let us know what was the context you were reading. From my perspective i think it was أشكال القناة الأليّة not أشكال الفتاة الأليّة القناة = ا+ل+ق+ن+ا+ة means " Channel " or "canal " it depends on the context. All the best

maybe it mean the mechanism girls forms