[Louis] 'son [Samuel] and [Samuel]'s grandfather [Harold] went on a cruise together. [Tracy] cycles with her brother [Louis] each Saturday. [Tracy]'s daughter [Laura] sometimes tags along when the weather is nice.
('Laura', 'Harold')
[Tracy] cycles with her brother [Louis] each Saturday. [Tracy]'s daughter [Laura] sometimes tags along when the weather is nice. [Louis] 'son [Samuel] and [Samuel]'s grandfather [Harold] went on a cruise together.
[{('Laura', 'grandfather', 'Harold'): [('Laura', 'mother', 'Tracy'), ('Tracy', 'father', 'Harold')]}, {('Tracy', 'father', 'Harold'): [('Tracy', 'brother', 'Louis'), ('Louis', 'father', 'Harold')]}, {('Louis', 'father', 'Harold'): [('Louis', 'son', 'Samuel'), ('Samuel', 'grandfather', 'Harold')]}]
['mother', 'brother', 'son', 'grandfather']