This is a mirror-ish matchup against another colorless prison deck, so Disruptor Flute gives us a flexible tax piece. Naming Chalice of the Void makes it cost {3} more, and naming a key spell like Kozilek's Command or Thought-Knot Seer taxes it the same way. Flute only affects spells with the chosen name and non-mana activated abilities, so naming a land like Eldrazi Temple does nothing. Lotus Petal is cuttable since both decks are racing to deploy threats and we want more disruption pieces than acceleration redundancy. Keep Karn, the Great Creator and The One Ring as the primary path to outvalue their Eldrazi beaters.