REMOVE

1. rock
2. valleys (landforms)
3. barriers
4. roads

WHAT

1. Visual Works (hierarchy n … (1)
2. atmospheric perspective (1)
3. black-and-white film (1)
4. bridges (built works) (1)
5. chairs (furniture forms) (1)

More 

WHERE

1. Three Brothers Islands, N … (1)

WHO

1. Clyfford Still; Still, Cl … (1)
2. Still, Clyfford (1)

WHEN

1. 1934 (1)
2. 1935 (1)
3. ca. 1934-35 (1)