2 1 activity [: , ] activity : , :call, : , :manipulate parallel :wait => do 1 end loop pre_test{ } post_test{ } do 1 end choose do 1 end 1 alternative do 1 end 1 otherwise do 1 end 1 parallel_branch do | | 1 end , : => [ ] " " { : => } , do | | 1 end