Painting in museum

I've been trying to find out what expressionist painting Karl/Cassiel is looking at in that museum when he has that powerful and debilitating flashback. It looks like something contemporary to Picasso and Braque and is definitely trying to portray some kind of horror...I'm sure Wenders had some real intention here, and that there was a reason the angels were crippled and the Nazis were laughing. I'd love to know the answer. Was it part of the exhibition on non-Aryan "degenerate art" the Nazis held in 1937?