Now combine grounds tied to neutral with a California 4-way and a receptacle between one of the 3-ways and the 4-way and you have Germany's most dangerous wiring contraption ever (depending on the position of the 3-ways the ground is tied either to the hot or neutral). Side note. unfortunately this kind of grounding (without California switching of course) was up to code and very common until 1973 in the West and 1990 in Eastern Germany.
