"I displayed also a poster by McKnight Kauffer"

Portrait of Edward McKnight Kauffer (c.1915)
Public DomainPortrait of Edward McKnight Kauffer (c.1915) - Credit: Raymond McIntyre (1879-1933)
 Edward McKnight Kauffer (1890-1954) was an American-born artist who specialised in graphic design.

He is particularly well-known for his London Transport and London Underground posters which drew on many artistic traditions, including futurism and cubism.

His work can be seen here and here.