How can you create a combo with Urza, Prince of Kroog, Doubling Cube, Ring of Valkas?
user
[START OF COMBO]This combo can be formed with Urza, Prince of Kroog, Doubling Cube, Ring of Valkas

Color identity: WU
Mana cost: {11}
Steps:
  1. Float at least {11}.
  2. Activate Doubling Cube by paying {3} and tapping it, adding at least {8}.
  3. Activate Urza by paying {6}, creating a token copy of Doubling Cube that is a 1/1 Soldier.
  4. Activate Ring of Valkas' equip ability by paying {1}, attaching it to the Doubling Cube token.
  5. Repeat from step 2 using the Doubling Cube token instead.
  6. Once you have infinite mana, you may target any artifact you control to get infinite copies of them.[END OF COMBO STEPS]

Result:
  - Infinite copies of each artifact you control
  - Infinite creature tokens
  - Infinite enters the battlefield
  - Infinite mana permanents you control can produce[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - All permanants must be on the battlefield
[END OF COMBO PREREQUISITES]
assistant