Challenge is a type of Invite. Invite is related to Join. 
Blue is related to Pizza. you are likely to find Pizza in/at/on Restaurant. you are likely to find Reception in/at/on Restaurant. Reception is related to Sound. 
Challenge --IsA--> Invite <--RelatedTo--> Join 
Blue <--RelatedTo--> Pizza --AtLocation--> Restaurant <--AtLocation-- Reception <--RelatedTo--> Sound 