Visitors at Escher-style installation outside London's Tate Visitors view an installation entitled 'Endless Stair' designed by de Rijke Marsh Morgan Architects (dRMM) near the Tate Modern gallery in central London. Inspired by MC Escher's famous surreal drawings of never-ending staircases, it was created to mark the launch of the London Design Festival which runs from 14th - 22nd September. Images