User blog comment:GamesFan2000/HNEAN (Part 3: Layered Arrays 1)/@comment-25601061-20181112133238/@comment-37246647-20181112184420

You evaluate the array after the {1} before you create the definer array. So, the definer would be {3, 3} entries long, all entries being 3, and the answer to that is how long the actual linear array is.