In 1997 , Groening , along with former Simpsons writer David X .
The shorts would be spun off into their own series : The Simpsons , which has since aired 639 episodes .
In 1997 , Groening , along with former The Simpsons writer David X .
The shorts would be spun off into their own series : The Simpsons , which has since aired 639 episodes .