{T}: Add one mana of any color to your mana pool. Spend this mana only to cast instant or sorcery spells.

Whenever you cast an instant or sorcery spell, put a memory counter on Pensieve. Then, you may cast an instant or sorcery card with converted mana cost equal to or less than the number of memory counters on pensieve from your graveyard without paying its mana cost. If you do, exile it as it resolves.