text: const Rx = require('rxjs/Rx');
  const number$ = require('../../util/example-streams.js').number$;
  
  // ASSIGNMENT: create a new stream that emits the square of each number emitted by the number$ stream.
  
  const squaredNumber$ = null; // ???
  
  // If implemented correctly, the application will output the following numbers: 1, 81, 16, 49, 36, 4, 4, 49, 9, 16, 64
  
  squaredNumber$.subscribe((x) => console.log(x));