Urza, Lord Protector, The Mightstone and Weakstone, The Chain Veil, Dross Scorpion, and Ashnod's Altar

Prerequisites

• Urza, Lord Protector on the battlefield
• The Mightstone and Weakstone on the battlefield
• The Chain Veil on the battlefield
• Dross Scorpion on the battlefield
• Ashnod's Altar on the battlefield
• Urza, Lord Protector and The Mightstone and Weakstone melded into Urza, Planeswalker

Steps

1. Activate Urza, Planeswalker's third loyalty ability by putting no loyalty counters on it, creating two 1/1 Soldier artifact creature tokens
2. Activate Ashnod's Altar twice by sacrificing the two Soldiers, adding
3. The Soldiers die, triggering Dross Scorpion twice, untapping The Chain Veil and any other artifact you control
4. Activate The Chain Veil by paying and tapping it, allowing you an additional activation of your planeswalkers' loyalty abilities this turn
5. Repeat

Results

• Infinite activations of loyalty abilities of all other Planeswalkers you control
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana artifacts you control can produce
• Infinite sacrifice triggers
• Infinite untap of artifacts you control