The document describes a foldable structure that opens when approached and covers a whole area when unfolded, made of irregular shapes like castle stones. It remains 'invisible' when folded and suggests continuing the lower area of a facade.

2. Opens when approached -> suggestion to continued lower area of facade
Foldable structure
‘Invisible’when folded
Covers whole area when unfolded
Made out of regular-irregular (castle stones) shapes -> eg. voronoi