I don't think this is what hayley-patton meant (although it's not crystal clear). I think SBCL does memory management with a bump allocator and a moving collector. So if you build a linked list sequentially, the cons cells will be allocated sequentially, and will be sequential in memory. If you build it in random order, they won't be. But when the collector runs, it will move the whole list, and it will move the cells in sequential order, and then it will be.
