Umbral Mantle T3-4 infinite

[Destore117]

T1 Forest
{Bird of Paradise}
T2 Land (island If possible)
{Training Ground} either from Island or bird
T3 Land
{Umbral Mantle}
Equip to birds and use it's mana ability to tap
Pay the one. Untap. Repeat
OR
Wait til T4 to T3 enchant birds with a {Aqueous Form} or Hexproof like {Alpha Authority}

Anyways
Combo is
Mana dork
{Training ground}
{Umbral mantle}

[Chargingswadger]

I use the mantle and {sword of the paruns} in my ezuri edh deck. It can go infinite with {priest of titania} {elvish archdruid} and {rofellos, llano war emmisary} and then I get infinite mana as well to activate ezuris second ability.