The Great Wall

Vigilance, Defender, Double strike, Reach.
All walls you control get +1+1 and vigilance.
Whenever a wall deals combat damage to a
creature or player, draw a card.
{x}{x}:Walls you control get
+X+X until end of turn. if X is 4 or more, walls
lose defender until end of turn.
{t}:Add one mana of any color.