text: // 2-way communication while a generator is running
  // long-lived while loops which do not freeze your program
  
  function* calculator(input) {
    var doubleThat = 2 * (yield input / 2);
    var another = yield doubleThat;
    return input * doubleThat * another;
  }
  
  const calc = calculator(10);
  
  console.log(calc.next());
  
  console.log(calc.next(7));
  
  console.log(calc.next(100));
  