When a door or a window transform into an impenetrable wall they present an obstacle tha seems immense. Sometimes is there, sometimes not, but it's present is always felt. 
The force that pushes me back when i come close is much greater than mine, although often i see glimpses of light coming through the cracks. Trying to understand it's origin, the meaning of the wall involves a search within me. So far it seems monolithic, completely out of reach and uknown.