[Tracy]'s brother [Robert] and sister [Beverly] went on a cruise with [Beverly]'s son, [Paul]. [Harold] 'son [Robert] could not believe that his father bought him a coffee machine for his birthday.
('Harold', 'Paul')
[Harold] 'son [Robert] could not believe that his father bought him a coffee machine for his birthday. [Tracy]'s brother [Robert] and sister [Beverly] went on a cruise with [Beverly]'s son, [Paul].
[{('Harold', 'grandson', 'Paul'): [('Harold', 'daughter', 'Beverly'), ('Beverly', 'son', 'Paul')]}, {('Harold', 'daughter', 'Beverly'): [('Harold', 'daughter', 'Tracy'), ('Tracy', 'sister', 'Beverly')]}, {('Harold', 'daughter', 'Tracy'): [('Harold', 'son', 'Robert'), ('Robert', 'sister', 'Tracy')]}]
['son', 'sister', 'sister', 'son']