Porosity

Filled with glass, hinged for air, set back for protection, bounded with strips of wood or metal, windows come in limitless variety, but not usually on one façade.  Except at Ronchamp.
Le Corbusier’s intent was to connect the sacred chapel with the whole of creation outside.  The primitive shape of Notre Dame du Haut responds to the hillside site and its legacy of occupation since pre-Roman times.  The openings depart from Corbu’s principles of standardization embodied in his residential projects, to create indirect and asymmetrical light within the chapel, causing areas to be bright or dark, and offering the luxury of choice as light shifts throughout the day.  A clerestory gap between the plane of the wall and the roof encourages contemplation of the upward motion of the swelling ceiling plane and the continuity between inside and out.  The concrete wall widens from a narrow point to three meters, permitting the openings to be deep-set from both of the outer planes, streaming light along the angled folds of the (surprisingly, nonbearing) wall.   
Most windows have rational openings, foursquare and regular, to admit light.  The extraordinary openings at Ronchamp are non-randomly scattered, anchored in the thick volume of the wall filled with the rubble of the previous chapel on the site (destroyed during World War II.)  Are the sparks of color like the stars in the sky, or the map of inhabitation on this Earth?  The array encourages wonder and attention, encourages visitors to get closer, to explore the possible connections, and to encounter the unexpected.  
 
Le Corbusier wrote Le Poeme de l’Angle Droit (The Poem of the Right Angle), at roughly the same time he was designing Ronchamp:
The law of the meander is
      active in the thoughts and
      enterprises of men forming their
      ever renewing avatars
             But the trajectory gushes out
      from the mind and is projected by
      the clairvoyants beyond
      confusion