def server [channel:^Int ack:^[]] =

     channel?i = (channel!(i+1) | ack?[] = server![channel ack] )

new lock:^[]

def client [chan:^Int ack:^[] n:Int] =
     
     lock?[] = (chan!n | chan?num = (ack![] | lock![] | printi!num)


run( new ch1:^Int

     new ack:^[]

     lock![] 

     (  server![ch1 ack]

      | client![chan ack 3]

      | client![chan ack 5] 
       
      )