The Dutch government requires that a percentage of the cost of any new public building be dedicated to the provision of artwork.
When the "new" TWR/APP block was built at EHBK around 1990 a number of coloured aluminium tubes were suspended from the ceiling of the Briefing Office to represent the Airways ( a red one, a green one, a blue one - you get the picture). The day before the official opening, somebody (no names, no pack drill) inserted a length of plain aluminium pipework into the display. Nobody even seemed to notice it, and it remained there for quite a while.Airway Alminum One