REMOVE

1. trains (vehicle groupings)
2. Still, Clyfford
3. 1930
4. between 1923 and 1933

WHAT

1. Visual Works (hierarchy n … (1)
2. machinery (1)
3. railroads (1)

WHO

1. Clyfford Still; Still, Cl … (1)

WHEN

1. 1923 (1)