Kaleidoscopic Windmill

Kaleidoscopic Windmill is all colors.
{t}: Add one mana of any color.
Whenever an opponent draws one or more cards,
or one or more cards they own in exile leave
exile; that player Mills 2 cards.
Rainbow: Each opponent's turn Mills 7 cards at
the end of their turn.. (As long as one mono-color
permanent of each color is in play, the game has
rainbow.)