Joseph Cornell (1903-1972) Untitled (Bird) 1949. At first sight very simple, but in reality it has great depth in structure and elements. For thorough description click on the website from which I pinned.
joseph cornell "museum"
Accumulations in a Box - Artworks - Official Website of ARMAN
Joseph Cornell American, 1903–1972, Dovecote (Colombier)
Joseph Cornell: Owl Box,1945-6. Cornell was a self-taught but accomplished artist who worked in mixed media, well known for his boxes.