lane actor#1 "judge" @4:15
lane actor#2 "s" @12:20
region seq#1 seq
region loop#1 loop parent=seq#1 @5:1 label="even"
region branch#1 branch parent=loop#1 @6:15
step ask#1 ask "judge" @6:34 lane=actor#1 region=branch#1 maybe serial
step ask#2 ask "s" @12:31 lane=actor#2 region=seq#1 always
edge ask#2 -> ask#1 data maybe exact
edge ask#1 -> ask#1 carry maybe
sink ask#1
