building cleaners glass washers window workers agile angles appearances architecture cleaning contemporary contrast contrasting curve curved danger dangerous dangling distant elements exterior external hanging height high high-rise light lighting linear lines metal modern perspectives ropes shadows shapes size sunlight supported supporting supports suspended suspension views wall washing window-cleaners windows work workmen aloft altitude block England english exposed exposure Great Britain landmark London risk shard sheer side skyscraper tourist attraction tower UP vulnerable appearance attendants brushed brushes carwash clean conveyor conveyorized drying equipment fixed cleaning mechanisms high pressure water streams human greeter mechanized mechanized car washes mitters nozzles protectants recycle reuse rinse rollers soaps soft cloth track trickling tunnel entrance tunnel exit tunnel washes vehicle wash stations washing processes waste-water water water reuse windscreen wraparounds