text: function delay(seconds, callback) {
    setTimeout(callback, seconds * 1000);
  }
  console.log('starting delays');
  delay(2, () => {
    console.log('two seconds');
    delay(1, () => {
      console.log('three seconds');
      delay(1, () => {
        console.log('four seconds');
      });
    });
  });
  