Sister is related to Daughter. Daughter is related to Dad. Dad is related to Name. Number is a type of Name. 
Coal is related to Dirty. Dirty is related to Pig. Pig is related to Animal. 
Sister <--RelatedTo--> Daughter <--RelatedTo--> Dad <--RelatedTo--> Name <--IsA-- Number 
Coal <--RelatedTo--> Dirty <--RelatedTo--> Pig <--RelatedTo--> Animal 