Orzhov Cluestone

A two-color fixing artifact with a built-in expiration date: it earns its keep smoothing the opening turns, then sits as dead weight once both colors are flowing. The self-sacrifice clause is the answer to that, an exit ramp that turns spent fixing into a fresh card. What pins down the design tension is the price on that exit: cracking it costs a white, a black, the tap, and the artifact itself, a steep enough tax that you rarely want to pay it during the early turns when the fixing actually matters. The card wants to be in play during the very turns when sacrificing it would be the last thing you would do, and it cashes out only once you would happily trade it away. The lineage runs back to ramp pieces that refund themselves, the cycling lands chief among them: fixing that does not strand you when you draw it late. At three mana it is slower and clunkier than the cheaper two-mana rocks that came to dominate the slot, and its mana ability is a plain tap-for-one-of-two, but the cash-out is why this kind of fixing aged into a reasonable floor for grindy two-color builds rather than a strict liability. A mana source that knows when to stop being a mana source is doing more design work than its two activated lines suggest.