This requires 2 DS's and 2 games. You can have whatever starter pokemon you want. Then, trade with your friend or yourself. Get all 3 starter pokemon. Okay, now you got Fire, Water, and Grass. Now, get a powerful Flying and Electric pokemon. Now you got all the types you should have. Fire for Grass, Water for Fire, Grass for Ground and Water. Flying can be switched with Psychic for fighting pokemon. Then Electric for Flying and Water.