Invitation is related to Come. Come is related to Demand. Call is a type of Demand. Call is related to Discussion. 
Break is related to Tear. Tear is related to Salt. Salt is related to Clear. Clear is similar to Perfect. 
Invitation <--RelatedTo--> Come <--RelatedTo--> Demand <--IsA-- Call <--RelatedTo--> Discussion 
Break <--RelatedTo--> Tear <--RelatedTo--> Salt <--RelatedTo--> Clear <--SimilarTo--> Perfect 