@prefix : <http://example/> .

# Two diamonds, with tail.
:a :p :b1 .
:b1 :p :n .

:a :p :c1 .
:c1 :p :n .

:n :p :b2 .
:b2 :p :y .

:n :p :c2 .
:c2 :p :y .

:y :p :z .