... Talking about PaulAndFlake's musical endeavors: Rammwiki says that Flake & Piet was Flake + his mysterious neighbor Piet, but here's what I found in Mix mir einen Drink:
Wenn gar niemand zu greifen war, machte ich eben mit Paul etwas. 1991 erschien unter den Namen Flake und Piet eine Kassette, die hieß »Goessel beinhart«. Abstrakt strukturierte Elektronik mit Titeln wie »Der Damenschneider« oder »Granatendub«. Ich habe mir die Kassette jetzt mal wieder angehört. Das ist wirklich harter Tobak. Junge, Junge, sage ich da nur.
Which I would (badly) translate as:
If no one else was available, I would do something with Paul. In 1991, a cassette was released under the name Flake und Piet, which was called "Goessel beinhart" ("Tough gosling"??). Abstractly structured electronics with titles such as "Der Damenschneider" ("The Tailor for Ladies") or "Granatendub" ("Grenades Dub"). I've listened to the cassette again lately. This is really tough stuff. Boy, boy, I'm just saying.
... From which I understand that Piet-the-neighbor is actually Paul. But I don't know for sure. Anyway, it sounds like a lot of fun.