global protocol SleepingBarber(role barber as B, role selector as S, role room as R) {
    rec Loop {
        choice at S {
            par {
                S introduces C;
            }
            enter() from S to R;
            choice at R {
                full() from R to C;
                returned() from C to S;
                wait() from R to B;
                continue Loop;
            } or {
                wait() from R to C;
                enter() from R to B;
                start() from B to C;
                stop() from B to C;
                done() from C to S;
                next() from B to R;
                wait() from R to B;
                continue Loop;
            }
        } or {
            done() from S to R;
            done() from R to B;
        }
    }
}