US Patent 7111431 Bulletproof observation tower

A watch or observation building having an observation section comprising a plurality of bullet proof panes having at least two side faces for observing surroundings. Each of these plurality of bullet proof panes lie next to one another with each face of the bullet proof panes meeting an adjacent face of an adjacent pane on a substantially vertical axis and press against each other along a horizontal direction. Each of the plurality of bullet proof panes face an observation direction such that a line perpendicular to a surface of each of said plurality of panes extends towards the different observation directions.