The Marble Girl attracted attention for its redefinition of the relationship between subject and material with its equal emphasis of the sculpture as woman figure and as stone block.

It was followed by smaller portrait heads of artist colleagues such as Niels Larsen Stevns and Ludvig Karsten, the boxer Dick Nelson (1918) and more children.

[2] Around the same time he collaborated with the architect Ivar Bentsen on a redevelopment of Blågårds Plads, a public square in one of the poorest working-class neighbourhoods in Copenhagen.

Its centrepiece, The Water Mother (Danish: Vandmoderen), features prominently in the winter garden of the Ny Carlsberg Glyptotek which also holds the original plaster model.

[3] Kai Nielsen died on 2 November 1924 while working on a draft for a Maritime Monument (1924, Ny Carlsberg Glyptotek) after several lengthy spells of illness.