you are likely to find Chair in/at/on Lobby. Back is part of Chair. Back is a type of Switch. 
Alarm is related to Fire. Fire is related to Department. Department is related to Store. Store can be used for Purchase. 
Lobby <--AtLocation-- Chair <--PartOf-- Back --IsA--> Switch 
Alarm <--RelatedTo--> Fire <--RelatedTo--> Department <--RelatedTo--> Store --UsedFor--> Purchase 