Involve is a synonym of Imply. Imply is a synonym of Mean. Mean is related to Angry. Angry is related to Riot. 
Boundary is related to City. City is related to Location. Location is related to Office. 
Involve <--Synonym--> Imply <--Synonym--> Mean <--RelatedTo--> Angry <--RelatedTo--> Riot 
Boundary <--RelatedTo--> City <--RelatedTo--> Location <--RelatedTo--> Office 