Crocheting Crossed Double Crochet Stitches

Dear users, dear authors,
What are crossed double crochet stitches, and what are they used for?

Does anyone else have anything to add?

A cross double crochet is a somewhat more "elaborate" type of double crochet that ends up having the shape of a cross :) 

Briefly explained: You start as if making a treble crochet, but don’t finish it. You leave loops on the hook. 
Then you start a second treble crochet, which you then finish. 
Now you don’t have a cross, but an upside-down Y. 
To finish the cross, you simply crochet another double crochet into the "gap" at the bottom. 
(But you’ll find various descriptions... Somehow everyone does it a little differently. What stays the same for all of them is that you end up with an X. 

I like this stitch, for example, especially in shawls or scarves, but airy tops can also be prettied up this way :) 

By the way, the cross double crochet should not be confused with the crossed double crochet, where you simply make one double crochet and then make the second double crochet behind the first.