The Everflowing Well // The Myriad Pools

The graveyard-as-fuel clock is doing the whole balancing job here. On the way in it mills two and draws two, digging while it seeds your yard, then does nothing but wait: each upkeep it checks whether the yard has filled to descend 8, and flips when it has. What waits on the back is the interesting part: an artifact that becomes a Land tapping for blue, plus a copy engine gated behind spending that specific mana. Every permanent spell you cast using The Myriad Pools' blue turns up to one other permanent you control into a copy of the spell being cast, a doubling effect wearing a mana-source costume. The tension is that the two halves want opposite things. The front wants to mill and dig, stocking the graveyard as fast as possible; the back wants a board worth copying onto and permanent spells left to cast. Because the transform trigger fires on your upkeep, the flip is never something you force at instant speed in response to a board state: you assemble the condition and it resolves on your own turn. The copy clause targets up to one other permanent you control with no legend restriction, so the ceiling is high and the setup is the price of admission. This suits a self-mill shell running a permanent-heavy curve, not one splashing it for a two-card dig.