@startuml
skinparam backgroundColor transparent
skinparam shadowing false
skinparam defaultFontName Monospace
skinparam defaultFontSize 12
skinparam rectangleBorderColor #2c7794
skinparam rectangleBackgroundColor #edf6fa
title A4 APPLICATION — deterministic participant topology
rectangle "01 coordinator p3\nBlocked: wait READY_ALL" as c
rectangle "02 worker A p2\nREADY_A then Blocked at barrier" as a
rectangle "03 worker B p1\nobserves partial mask\nsets final READY_B" as b
rectangle "04 coordinator\npreempts B\ncontributes SYNC_C" as cp
rectangle "05 worker B\ncontributes final SYNC_B" as bf
rectangle "06 verifier p0\nchecks masks, states, stacks, order" as v
c --> a
a --> b
b --> cp
cp --> bf
bf --> v
@enduml