This horn reminds me of the "peashooter" corners and trumpets from the early 20th Century. I have had two, a CONNqueror Art Deco model, and a Cavalier model, which is a stencil of Conn. The tilted portion is similar, though the main boretube was the one so tilted. It connected to the third valve in the back instead of the front, and the third valve running slide was moved to the front. This design is very interesting!