Extended families pooling their resources and getting more bang for the buck (or euro).
I like this even better than a multiplex. The layout of the buildings creates an internal courtyard and no shared walls.
Shown on S5E8 of Extreme Homes.
The house is construed as three separate units for three sisters and their families: All houses share beautiful views and good orientation, as well as a certain degree of interconnectedness. They stand together but don't intersect. Next to the volumes there is a garden, an olive grove and a shared courtyard.