Curve is a type of Pitch. Curve is related to Twist. Twist is related to Music. 
Sand is related to Water. Water is related to Sink. Sink is a synonym of Drop. Drop is related to Wet. 
Pitch <--IsA-- Curve <--RelatedTo--> Twist <--RelatedTo--> Music 
Sand <--RelatedTo--> Water <--RelatedTo--> Sink <--Synonym--> Drop <--RelatedTo--> Wet 