Feininger is best known for images that were probably originally inspired by Cubism, but usually lacked the Cubist rationale that subjects were supposedly simultaneously depicted from various points of view in one image. Instead, Feininger simplified subjects using straight edges and planes, often extending edge lines across the picture plane accompanied by transitional value shading. The result was a clean, somewhat crystalline appearance that has appealed to me for as long as I can remember. Other artists picked up on this, including C.R.W. Nevinson and Ray Hill, the latter an instructor at the University of Washington when I was an art student.
Below are examples from what I consider to be Feininger's Golden Years.
This seems to be about as Cubist as Feininger could manage.
Even people are reduced to lines and angles.
A crystalized landscape.
Another somewhat Cubist image.
Gothic arches are reduced to angles here.
The bird's wings seem Futurist-inspired (think: Giacomo Balla's Dinamismo di un Cane al Guinzaglio -- "Dynamism of a Dog on a Leash" - 1912).