It's an image of ascent toward heaven, from which the boy returns.

这是接近天堂的的样子，从那里，这个孩子又回到地面。

耶鲁公开课 - 现代诗歌课程节选

And then he goes back to hell and then back up to heaven -goes back and forth between these two rhythmically very different concepts.

然后它回到了地狱,接着又升到了天堂,在这两种节奏非常不同的概念之间,来回往复

耶鲁公开课 - 聆听音乐课程节选