How can you create a combo with Yedora, Grave Gardener, Phyrexian Altar, Watcher of the Roost?
user
[START OF COMBO]This combo can be formed with Yedora, Grave Gardener, Phyrexian Altar, Watcher of the Roost

Color identity: GW
Mana cost: 
Steps:
  1. Activate Phyrexian Altar by sacrificing Watcher of the Roost, adding one mana of any color.
  2. When Watcher of the Roost dies, Yedora triggers, returning Watcher of the Roost from your graveyard to the battlefield face down as a Forest land.
  3. Activate Watcher of the Roost's morph ability by revealing a white card from your hand, turning it face up.
  4. Watcher of the Roost triggers, causing you to gain 2 life.
  5. Repeat.[END OF COMBO STEPS]

Result:
  - Infinite colored mana
  - Infinite death triggers
  - Infinite landfall triggers
  - Infinite lifegain
  - Infinite lifegain triggers
  - Infinite leaves the battlefield
  - Infinite sacrifice triggers[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - All permanants must be on the battlefield
  - You have at least one white card in hand.
[END OF COMBO PREREQUISITES]
assistant