Foreground and in the background compared to another element

Good afternoon,

I'm using Illustrator and I would like to have an effect like the one in image attached.

I don't know how to call it so I'm not able to find any info in web.

Essentially I would like to make sure that an element appears at the same time in the foreground and in the background compared to another element present in the work table. See for example the letter H in the image