Swamp Oasis enters the battlefield tapped unless you control one or more lands.
: Add or to your mana pool.
Put Swamp Oasis on top of your library: Add to your mana pool.
, Sacrifice Swamp Oasis: Add to your mana pool.
: Add 
or 
to your mana pool.
to your mana pool. , Sacrifice Swamp Oasis: Add 
to your mana pool.
