Conversation so far:
What was Rem Koolhaas' proposal about the European Flag?
Rem 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.
What kind of symbol was the Barcode?
In the barcode, new Member States of the EU can be added without space constraints.

Question: Why did they decide to unite the flags?
Self-contained rewrite: Why did Rem Koolhaas and his think-tank AMO decide to unite the flags?