Sam, Windmill Slammer

Whenever you draft a card that does not share a
color with the last card you drafted, reveal and
make a note of it.
Before you shuffle your deck to start the game,
reveal this card from your deck and exile a number
of cards you drafted that aren't in your deck up to
the number noted.
{r/g}{r/g}{t}: Cast a card exiled with Sam, Windmill
Slammer at random.