Comfortable is related to Safe. Safe is a different concept from Drop. Drop is related to Catch. 
Course is related to Feeling. Feeling is related to Wet. Wet is related to Mud. Mud is related to Chocolate. 
Comfortable <--RelatedTo--> Safe <--DistinctFrom--> Drop <--RelatedTo--> Catch 
Course <--RelatedTo--> Feeling <--RelatedTo--> Wet <--RelatedTo--> Mud <--RelatedTo--> Chocolate 