10 UMLUseCase 600 20 80 80 SnapSwap Relation 470 40 150 50 lt=<- qual_in= qual_out= 130.0;20.0;10.0;20.0 UMLUseCase 420 30 60 60 Middle Man Relation 310 40 130 50 lt=<- qual_in= qual_out= 10.0;20.0;110.0;20.0 UMLUseCase 240 20 80 80 Bitstamp Relation 120 40 140 40 lt=<- $10 USD 120.0;20.0;10.0;20.0 UMLUseCase 70 30 60 60 Alice fontsize=11 UMLUseCase 760 30 60 60 Bob fontsize=11 Relation 670 40 110 40 lt=<- $0 USD 10.0;20.0;90.0;20.0