A Most Interesting Spout

I have this coffee pot. I've owned it for many years. It was part of a drip coffee set that has the pot on the bottom and a funnel-shaped porcelain filter holder that sits atop it. You insert a paper filter, fill it with grounds, pour hot water through the grounds and the coffee drips down into the pot. Not unusual.

But what is unique, at least to me,  is the spout on the pot. It has a very graceful shape. And the end of the spout has a groove on the underside and a small slot-like hole in it. The groove is angled with the spout shape, but the hole is level with the bottom of the pot.

Because of this design, not a drop develops on the end of the spout . Somehow, the groove and the hole causes the volume of the liquid to go back into the pot via the spout throat and not drip or cling to the end of the spout.

The pot was made in Germany and I have a feeling this design is one that has been used there, perhaps in other places in Europe, for a very long time.

I'm going to try and incorporate this design into my next teapot and see if I can get it to work.

Does anyone know the origin of this design and have any more information about it?