REMOVE

1. roads
2. landscapes (representations)
3. trains (vehicle groupings)
4. fences
5. 1945

WHAT

1. Visual Works (hierarchy n … (1)
2. exterior views (1)
3. fields (land) (1)
4. horizon line (1)

More 

WHERE

1. Killam, Alberta, Canada (1)

WHO

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

WHEN

1. 1920 (1)
2. between circa 1929 and ci … (1)