split between two separate buildings. The 15-storey west block is for residential use, providing 109 flats of which 53 are designated as affordable. The much larger horseshoe-shaped eastern block, standing 11 storeys high, encircles a publicly accessible courtyard comprising 27% of the site's area. It provides 37,625 m2 of office space with by far the largest floor plates of any office block in the West End of London, with 4,000 m2 on all but the top two floors. At ground level, 2,276 m2 of space is available for retail outlets and restaurants. The block is irregularly shaped with recesses, projections and roof terraces intended to make it look more interesting and to break up its bulk. The development was built on a speculative basis on the assumption that the office space would be taken by a handful of major corporate tenants. Legal & General's commission urged Piano to avoid designing a "plain vanilla office building" and called for the new development to be "a fantastic place for people to work". As an incentive, it offered to pay an extra 10% above the normal going rate for London office developments. Piano decided to take the commission because, as he put it, "the client and the company involved were all about long lasting quality, without rushing. It is very difficult to do a job with somebody who has a short vision – in the end it never works." At ground floor level, the bases of the buildings are open with concrete columns visible behind seven-metre-high ceiling-to-floor windows of low-iron glass, which offers greater transparency than normal glass. The courtyard plaza is ringed with eateries and shops, with two oak trees planted in the middle alongside art installations designed by the sculptors Steven Gontarski and Rebecca Warren. The treatment of the upper floors provides a striking contrast. 134,000 green, orange, lime and yellow glazed terracotta tiles cover the façades in 13 irregularly oriented vertical panels on the external perimeter. The façades facing the inner courtyard are lined with another eight panels covered with grey tiles, a design which project architect Maurits van der Staay says was intended to "ensure that the upper storeys did not detract from the transparency of the ground floor and to maximise the amount of light reflected back into the offices." The façades are hung on an internal chassis carrier system (a similar system is in use in another