Each of the main transport units has its own corporate identity, formed by differently coloured versions of the standard roundel logo and adding appropriate lettering across the horizontal bar. The roundel rendered in blue without any lettering represents TfL as a whole (see Transport for London logo), as well as used in situations where lettering on the roundel is not possible (such as bus receipts, where a logo is a blank roundel with the name "London Buses" to the right). The same range of colours is also used extensively in publicity and on the TfL website. Transport for London has always mounted advertising campaigns to encourage use of the Underground. For example, in 1999, they commissioned artist Stephen Whatley to paint an interior – 'The Grand Staircase' – which he did on location inside Buckingham Palace. This painting was reproduced on posters and displayed all over the London Underground. In 2010 they commissioned artist Mark Wallinger to assist them in celebrating the 150th anniversary of the Underground, by creating the Labyrinth Project, with one enamel plaque mounted permanently in each of the Tube's 270 stations. In 2015, in partnership with the London Transport Museum and sponsored by Exterion Media, TfL launched Transported by Design, an 18-month programme of activities. The intention is to showcase the importance of both physical and service design across London's transport network. In October 2015, after two months of public voting, the black cab topped the list of favourite London transport icons, which also included the original Routemaster bus and the Tube map, among others. In 2016, the programme held exhibitions, walks and a festival at Regent Street on 3 July. Typeface Johnston (or Johnston Sans) is typeface designed by and named after Edward Johnston. The typeface was commissioned in 1913 by Frank Pick, then commercial manager of the Underground Electric Railways Company of London (also known as 'The Underground Group'), as part of his plan to strengthen the company's corporate identity. Johnston was originally created for printing (with a planned height of 1 inch or 2.5 cm), but it rapidly became used for the enamel station signs of the Underground system as well. Johnston was originally printed using wood type for large signs and metal type for print. Johnston was redesigned in 1979 to produce New Johnston. The new family comes in eight members: Light, Medium, Bold weights with corresponding Italics, Medium Condensed and Bold