curtains! Foreign Office Architects' John Lewis in Leicester

To find an appropriate pattern, the architect delved into John Lewis’ 
archive, picked a couple of its fabric patterns, combined them and made 
then more geometric. Applied to the facades, the frond-like patterns 
became an optical device seen from both inside and outside.

As it was worked up into 3D architecture, several clever tricks were 
introduced. The double-skinned facade required two layers of net 
curtains in order to limit transparency, and the trick here was to line 
up exactly the same pattern on inside and outside layers. This creates a 
dual effect so that, when facing the facade head on, you can look 
straight through the gaps in the pattern, but when looking at an oblique 
angle, the two layers of patterns are offset and block your vision. So 
when you are inside the shop, you are offered liberating views out, but 
as the patterned facade starts at first floor level, views in from the 
outside are obscured. The two layers of obscure patterning also provide 
the practical benefit of sun-shading.

Next, depending on what it planned to place behind the facade, John 
Lewis asked for different levels of transparency. The wheeze here was to 
come up with four panel types with very similar patterns but varying 
thickness of fronds, so that the degree by which the transparency was 
reduced ranged from 34.25% to 43.47%, and the fronds all lined up at the 
panel edges so the four pattern types could be mixed and matched.

cont'd....
http://www.building.co.uk/story.asp?sectioncode=583&storycode=3112467&c=1