Shore is a synonym of Reinforce. Reinforce is a synonym of Strengthen. Strengthen is a synonym of Tone. Tone is related to Music. 
Expensive is related to Oil. Oil is related to Mud. 
Shore <--Synonym--> Reinforce <--Synonym--> Strengthen <--Synonym--> Tone <--RelatedTo--> Music 
Expensive <--RelatedTo--> Oil <--RelatedTo--> Mud 