No blending. Duck should be yellow everywhere.
Simple blending. Duck should be a horizontal rainbow inside, and blue on overflow.
Parent is a stacking context. Duck should be a horizontal rainbow inside, and yellow on overflow (since there is no background there to blend with).
Intermediate parent - no stacking context. Duck should be a vertical gradient inside, and blue on overflow.
Intermediate parent with grandparent stacking context. Duck should be a vertical gradient inside, and yellow on overflow.
Intermediate parent has overflow. Duck should be a vertical gradient inside, and overflow is hidden.