Behind each of the goals, yellow and red cards will produce two enormous Catalan flags

‘Som i serem’ (‘We are and we will be”) is the slogan that will appear in the mosaic being prepared for Saturday night’s crunch encounter between Barça and Madrid, a match that will be watched by an expected 400 million people around the world. The mosaic, consisting of 90,000 coloured cards, will stretch right around the stadium and will be unveiled just as the teams are emerging out of the tunnel. The words ‘Som i serem’ will fill both the touchline sections of the stadium, against a background of the Barça colours. Behind each of the goals, yellow and red cards will produce two enormous Catalan flags.