Is it blue or is it green? SOM has designed a building for London's Docklands which uses a special new paint which changes its colour according to where you stand and the condition of the light. Arrowhead Quay, a recently-approved 49,300m 2headquarters building, features a specialist mica paint applied to its mullions which has been used in fashion (on ties) and on Alfa Romeo cars but never before on a UK building. The scheme, by developer Ballymore Properties, has vertical and horizontal mullions and features a doubleheight glazed lobby and vertical atria, which will have glass floors.SOM director Nicholas Jacobs said the paint, by Pittsburgh Paints, is 50 per cent more expensive than metallic paint, itself twice as much as standard paint. But it has been tried before by architects Rafael Vinoly in Japan and Frank Gehry on his Experience Music project in Seattle, US. Ballymore is also waiting for planning approval for two alternative applications for an office led development at 1 Millharbour - one for a 37-storey scheme, the other for a 25storey scheme. Both are designed by Michael Squire and Partners.