[Harold] loved teaching his son, [Pedro], baseball. [Harold] went bike riding his grandson [Samuel]. [Samuel]'s father [Louis] was skateboarding. [Robert] went to the baseball game with his brother [Louis].
('Robert', 'Pedro')
[Robert] went to the baseball game with his brother [Louis]. [Harold] went bike riding his grandson [Samuel]. [Samuel]'s father [Louis] was skateboarding. [Harold] loved teaching his son, [Pedro], baseball.
[{('Robert', 'brother', 'Pedro'): [('Robert', 'brother', 'Louis'), ('Louis', 'brother', 'Pedro')]}, {('Louis', 'brother', 'Pedro'): [('Louis', 'father', 'Harold'), ('Harold', 'son', 'Pedro')]}, {('Louis', 'father', 'Harold'): [('Louis', 'son', 'Samuel'), ('Samuel', 'grandfather', 'Harold')]}]
['brother', 'son', 'grandfather', 'son']