The description, which says that you can start at any of the first 12 words, doesn't seem quite right; you can start on any of the first 8 words and it works, which seems amazing (but apparently isn't—I haven't read the linked analysis), but starting at the 9th ('sitting') or the 11th ('her') will leap-frog you right over 'sister'. (I suppose it's debateable whether or not this 'works' starting at the 12th word, depending on whether you count starting there as winding up there.)