2RRR? Why, that's how much mana I get from Seething Song!
Which of course costs 2R, a cost I pay for with Desperate Ritual.
1R, a perfect cost from Rite of Flame!
Tap a mountain and HERE WE GO!
(Seven mana is also how much mana I need to play and activate belcher.)
It's interesting how much difference there is between 8 mana for Minotaur Storm and 9 mana for Dragonstorm.