Pile is a type of Thread. Pile is related to Mountain. Mountain is related to Pass. Pass is a synonym of Transit. 
Expression is related to Smile. Smile is related to Happiness. Happiness is a type of Mood. Mood is related to Better. 
Thread <--IsA-- Pile <--RelatedTo--> Mountain <--RelatedTo--> Pass <--Synonym--> Transit 
Expression <--RelatedTo--> Smile <--RelatedTo--> Happiness --IsA--> Mood <--RelatedTo--> Better 