It's made on the same principle as the ancient greek garment, the Chiton -popularised by the Ionic Greeks and promptly stolen by the Romans.. here's a couple of pictures that illustrate its simple elegance.
The modern version I have has several buttons at the "top", and the "neckhole" is wide enough that it can be worn in a number of ways, belted or unbelted.
You can just pop it over your head with the buttons running across the shoulder line.. or you can put one arm through the "neckhole" and wear it in a one-shoulder style, you can turn it around so the buttons run down the front and wear it that way, you can knot half or all of it and do any scarf ties you like.. you can wrap it around your waist in a sarong style.. you can belt it, or not.. you can pull it forwards to create a cowl neck or backwards for a scoop neckline at the back..
Here's several versions I came up with in a couple of minutes:
the one I have is a very light cotton with a transparent weave, it's red and has been printed with a paisley print that goes from black to purple. I've layered it over a simple red dress here but I know I will be wearing it with plenty of other things too.
next time I see a gorgeous scarf I will be tempted to pick up two of them so I can sew them together and make another one of these.. in fact, if I knew what this thing was called I'd already be searching the internet for more of them. Any ideas, people?