>>64216188 (OP)
The answer is and always will be Etrich and their licensed builder of Albatros, Aviatik, DFW, Gotha, Harlan, Halberstadt, Jeannin, Kondor, RFG, Roland and Rumpler.
Ironically, its designer, Igo Etrich, did not want his creation to be used in was beyond spotting and training, but this type also served as a bomber and a very early fighter in some cases where the pilot would shoot at the enemy observation aircraft, usually with a revolver.
Igo Etrich designed all of his aircraft with the wing in picrel and it is based off of the wings of a dove (hence the name of this aircraft being Taube, the German for dove) and a lot of the aforementioned German and Austro-Hungarian companies use modified versions of Etrich's wing, usually for the sake of simplified construction, hence, more square. The exception is Fokker (of which Anthony Fokker developed a similar aircraft, the Spin, or Spider, having thought that his finished aircraft looked like it was donning a giant spider's web), Junkers (which was the Blohn und Voss of WWI in that they used corrugated metal construction) and Zeppelin (which focused on larger bombers only).
Sorry for the sperg out, but I have been waiting to talk about this for a little while, now.