MTG >Combos >Gemstone Array +Doubling Season +Pir, Imaginative Rascal +

With all cards in play: Pay two mana to activate Gemstone Array's ability Pir and Doublin Season's ability will trigger, and instead of you adding a counter, you'll put three. Remove two counters from Gemstone Array to add two mana and activate its ability again Repeat the process for infinite mana.