Stern Lesson

The card-filtering half of this is familiar: draw two, ditch one, the same net advantage and selection that plenty of three-mana instants offer. What sets it apart is the Powerstone stapled to the back. That token is deliberately hobbled: it makes colorless mana that cannot be spent to cast nonartifact spells, so the acceleration it provides is walled off from the very kind of spell you just cast to make it. What it can still pay for is instructive, and this is where the effect turns directional rather than dead: casting artifacts, activating abilities, feeding ward costs, and any other cost that isn't casting a nonartifact spell. The design pays for the "free" mana by narrowing its use, which means Stern Lesson only fully cashes out in a shell that already wants restricted artifact mana: something laying down bigger artifacts, or an activated-ability engine hungry for colorless. Point it at a spellslinger deck and the Powerstone is close to inert, mana you cannot spend on the counterspells and cantrips you actually run. That tension is the whole point. Powerstones are an era-specific answer to a perennial ramp problem: how to accelerate without handing the same acceleration to every generically greedy deck. Stern Lesson leans into the gate rather than fighting it, offering competent filtering to any blue deck while quietly rewarding only the artifact-forward ones with the token's real value.