PREFIX : <http://example.org/test#>

:alice :mother _:b1 .
:alice :says { _:b1 a :NicePerson }.
:bob  :mother _:b2.
:bob  :says { _:b3 a :NicePerson }.
{ _:x :mother _:y; :says { _:y a :NicePerson } } => { :answer :is _:x }.
