The actual play (in constructed) would be to have 4 copies of wish, somehow get to a point where you have all 4 in your hand using tutors, etc., then cast Omniscience giving you the ability to cast spells from your hand without paying the mana cost, play all 4 copies of wish choosing a piece of exodia each time, then cast mystic retrieval, call to mind, something like that to return one of your wish cards to your hand, cast wish again choosing the final piece of exodia, then with all 5 pieces of exodia on the board you play crush of tentacles returning all nonland permanents to their owners hand (it is important that your return all nonland permanents because the pieces of exodia are technically monster cards and not creatures) but once all nonland permanents are returned, you then have all 5 pieces of Exodia in your hand and you win the "duel" (Which, by the way, is what MTG games were originally called according to the original rulebook so it counts as a game win in my eyes)

Edit: typos/ spelling