Start point and Node A are not centered in Bob's lane:
@startuml |Bob| start :A; |Alice| :B; fork |Alice| :B_1; |Bob| :C_1; end fork again |Alice| :B_2; :B_2_1; |Bob| :C_2; end fork again |Alice| :B_3; :B_3_1; end end fork @enduml
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