HDTV is said to have a 16 by 9 aspect ratio. The picture is 16 units wide and 9 units high. Regular TV has a 4 x 3 ratio, adopted to match the format of motion pictures which had been using a 4 x 3 image about since the time of Thomas Edison.
But during the crazy Weimar Republic restless German filmmakers were looking for ways to not be quite so 4 x 3 all the time. These stills from Ernst Lubitsch's 1920 "Sumurun" show some of his efforts at reframing the scene out of the usual box:
There are many of the classic "iris" effects:
Here's Ernst Lubitsch himself, as a hunchback:
At times the iris is used almost like a zoom lens:
The iris didn't have to be centered either. It could start in one corner to isolate a detail and then grow to reveal the whole scene.
Very slight vignetting in old films is so common that I've often wondered if it might just be a lens defect.
Lubitsch doesn't only do circles. Here's a "widescreen" that is almost 16 x 9...
He goes vertical to capture this guy tumbling down a sand dune:
Hmmm... how to frame some eunuchs on a stairway....
There are also more decorative shapes:
You might argue that those are intended to be a view through some architectural element of the set but they are never really established as the point-of-view of anyone.
Finally... the blob:
You'll notice these all have a tint to them. That was often done at the time, but in this instance it doesn't seem to follow the typical "blue is night" sort of scheme. There must be some other psychological message intended.