Stacking of shapes and/or volumes is a rather trendy thing in architecture at the moment, I'd reckon. I don't know who started the trend, but a lot of architects are into this concept. Some of the biggest names in architecture are doing it. O.M.A. does it a lot, lately (for instance, in their Bryghusprojektet in Copenhagen, or the Hamburg Science Center). Also JDS (Julien de Smedt) used this concept in his proposal for a Villa in China.
But also in the work of Herzog & De Meuron one can see a proliferation of this concept: for instance in their 56 Leonard Street skyscraper in New York, or the Projet Triangle in Paris. Or even the original proposal for the extension of the Tate Modern in London was based around this concept.
With that being said and done: I recently saw some photos of the construction of the Vitra Haus in Weil am Rhein, like the picture above (from flickr.com user Dom Dada). This project by Herzog & De Meuron looked as a simple schematic "stacking of typical house-shaped volumes" the first time I saw this project (on platforma arquitectura.
But the the construction photos show the actual physical quality that is achieved by such a simple concept. I think it's typical for many of the projects by Herzog & De Meuron: the renderings/drawings make you think "is that really all? It looks a bit dull..."; the construction phase makes you think "well, this appears to be more promising than I thought before, it seems to have some unexpected spatial qualities..."; and the materialized building actually leaves you awestruck. That's exactly what I like about their work in general (and this Vitra Haus specifically): in many architectural projects, the building is not nearly as sophisticated and elegant as the initial renderings; but for Herzog & De Meuron's work it's the exactly the other way around: the building is always better than the drawings.