4 defenders equals infinite mana

Equipped creature has ", : This creature gets +2/+2 until end of turn." ( is the untap symbol.) Equip

Defender , : This creature deals damage to target player or planeswalker equal to the number of creatures you control with defender.

Each opponent loses X life. You gain life equal to the life lost this way.

Defender : Add X mana in any combination of colors, where X is the number of creatures you control with defender.

Defender : This creature deals 1 damage to each opponent. Whenever you cast a multicolored spell, untap this creature.