// Subscribe starts the clock, and will emit after 1 second
sequence.subscribe({
  next(num) { console.log('1st subscribe: ' + num); },
  complete() { console.log('1st sequence finished.'); }
});
 
// After 1/2 second, subscribe again.
setTimeout(() => {
  sequence.subscribe({
    next(num) { console.log('2nd subscribe: ' + num); },
    complete() { console.log('2nd sequence finished.'); }
  });
}, 500);
 
// Logs:
// (at 1 second): 1st subscribe: 1
// (at 1.5 seconds): 2nd subscribe: 1
// (at 2 seconds): 1st subscribe: 2
// (at 2.5 seconds): 2nd subscribe: 2
// (at 3 seconds): 1st subscribe: 3
// (at 3 seconds): 1st sequence finished
// (at 3.5 seconds): 2nd subscribe: 3
// (at 3.5 seconds): 2nd sequence finished