Decks that rely on fast mana, like combo decks, can go as low as 14 lands, as they make use of mana rocks like Lotus Petal or cards like Dark Ritual to add mana and cast as many spells as they can to execute their combo
Once its out, you get constant knowledge of your top card and the green light to cast creatures from there
Bristling Hydra: [Category 2] ETB yield is 3 Energy for 4 mana, then you can spend 3 Energy to place a +1/+1 on this creature and give it end of turn Hexproof
This means Food chain should net five mana per loop
In this case, flipping doesn't mean throwing the card in circles from one foot about the playing area like with Chaos Orb
It's also a discard spell, a removal spell, a sweeper, an Affinity hoser, and a way to deal with Karn Liberated, all for just two mana