Background: Remment Lucas "Rem" Koolhaas (Dutch pronunciation: [rem ko:lha:s]; born 17 November 1944) is a Dutch architect, architectural theorist, urbanist and Professor in Practice of Architecture and Urban Design at the Graduate School of Design at Harvard University. Koolhaas studied at the Architectural Association School of Architecture in London and at Cornell University in Ithaca, New York. Koolhaas is the founding partner of OMA, and of its research-oriented counterpart AMO based in Rotterdam, the Netherlands. In 2005, he co-founded Volume Magazine together with Mark Wigley and Ole Bouman.
Context: Following the signing of Treaties of Nice in May 2001, which made Brussels the de facto capital of the European Union, the then President of the European Commission, Romano Prodi and the Belgian Prime Minister Guy Verhofstadt invited Koolhaas to discuss the necessities and requirements of a European capital.  During these talks and as an impetus for further discussion, Koolhaas and his think-tank AMO - an independent part of OMA - suggested the development of a visual language. This idea inspired a series of drawings and drafts, including the "Barcode". The barcode seeks to unite the flags of the EU member countries into a single, colourful symbol. In the current European flag, there is a fixed number of stars. In the barcode however, new Member States of the EU can be added without space constraints. Originally, the barcode displayed 15 EU countries. In 2004, the symbol was adapted to include the ten new Member States.  Since the time of the first drafts of the barcode it has very rarely been officially used by commercial or political institutions. During the Austrian EU Presidency 2006, it was officially used for the first time. The logo was used for the EU information campaign, but was very negatively criticized. In addition to the initial uproar caused by the Estonian flag stripes being displayed incorrectly, the proposed flag failed to achieve its main objective as a symbol. Critics pointed the lack of capability to relate the signified (the mental concept, the European Union) with the signifier (the physical image, the stripes) as the major problem, as well as the presented justification for the order in which the color stripes were displayed (as every country in the EU should be regarded as equal in importance and priority).
Question: what color was the flag. Whats the answer?