User blog comment:Scorcher007/About Cofinality, sipmly/@comment-34422464-20190722143442/@comment-31580368-20190722145215

Perhaps this is one of the easiest explanations, we can even give a recursive definition

cf(0) = 0 cf(n) = 1, где n - successor ordinal cf(α) = cf(β), где α - limit ordinal, α = {x1,x2,x3,x4,...,xn,...}n<β

But I still think that it is not enough for beginners. I want to come up with some kind of analogy.