Karoo

This is where the bounce-land template was born. The Visions cycle ran the experiment in mono-color terms, one land per color, well before the Ravnica karoos generalized it to every guild pair: a tapland that charges you a return-a-Plains-to-hand cost just to stay on the battlefield, then pays you back two mana per tap. The structural discipline is the whole point. Entering tapped costs a turn of velocity; bouncing an untapped Plains costs a land drop's worth of tempo and resets a previous turn's progress; failing to pay sacrifices the land outright. What you buy with all that friction is two mana from one land in a color that wants more of it without a true ramp spell to lean on. The return clause is more than a tax, too: it lets you re-trigger comes-into-play effects on the bounced Plains and smooths a stumbling draw into a fixed one, the upside that kept the cycle worth printing despite the tempo hit. The Ravnica bounce lands later refined the skeleton (no sacrifice clause, two-color output, a cleaner return into a clean dual), but the chassis is here: a land that asked players to accept being a turn behind in exchange for doubling a single land's mana. Karoo is the prototype, the first attempt at solving the mana-density problem by spending tempo instead of life or card advantage.