De Kooning joined the Artists Union in 1934, and in 1935 was employed in the Federal Art Project of the Works Progress Administration, for which he designed a number of murals including some for the Williamsburg Federal Housing Project in Brooklyn. None of them were executed, but a sketch for one was included in "New Horizons in American Art" at the Museum of Modern Art, his first group show. Starting in 1937, when De Kooning had to leave the Federal Art Project because he did not have American citizenship, he began to work full-time as an artist, earning income from commissions and by giving lessons. That year de Kooning was assigned to a portion of the mural "Medicine" for the "Hall of Pharmacy" at the 1939 World's Fair in New York, which drew the attention of critics, the images themselves so completely new and distinct from the era of American realism.