Variety is related to Vary. Vary is related to Difference. 
Lamp is related to Lighting. Lighting is related to Bolt. Bolt is related to Spark. Spark is related to Jump. 
Variety <--RelatedTo--> Vary <--RelatedTo--> Difference 
Lamp <--RelatedTo--> Lighting <--RelatedTo--> Bolt <--RelatedTo--> Spark <--RelatedTo--> Jump 