Geonosian Droid Factory

{t} — Engineering 2
{r}, {t} — Sacrifice target Droid/Artifact.
Create two copies of it, which are tokens.
Sacrifice them at the end of this final step.
{b}, {t} — Sacrifice target Droid/Artifact.
Look at the top three cards of your library,
then put one of them into your hand.
{g}, {t} {line} Sacrifice target Droid/Artifact.
Engineering X, where X is the toughness of
the sacrificed creature