This variation grid and associated follow up task are, at first glance a drill exercise, however the scope for this task is wide.  Encouraging leaners to consider where they would like to start makes for interesting observations as the teacher walks around the class.  Many pupils will work horizontally, others will work vertically and others unsystematically.  The experience of using this task in class was not about focusing on practice of expanding brackets (as pattern spotting becomes inevitable), but on how the terms are generated.  The opportunity to generalise is built in, and in my experience, by the end of the lesson all learners could complete the furtherest right column by inspection.  The key idea is that the underlying structure of expanding brackets becomes apparent.  Extension was to explore patterns and behaviour in (x +1)^3, (x +1)^4, etc.  

Credit:  @chrismcgrane84