Biotower Schematics

At the end of each turn, if enchanted land is
untapped, put a schematic counter on it.
{t}Remove 3 schematic counters from enchanted
land and sacrifice Biotower Schematics. Search
your library, hand and graveyard for one
Biotower land and put it into play.
The biotowers were a failed experiment from a previous
war, but the Legate was willing to try anything.