Urza, Lord High Artificer, Worldwalker Helm, and Mirrorworks

Prerequisites

• Urza, Lord High Artificer on the battlefield
• Worldwalker Helm in hand
• Mirrorworks on the battlefield
• available

Steps

1. Cast Worldwalker Helm by paying
2. When Worldwalker Helm enters the battlefield, Mirrorworks triggers, causing you to pay to create a token copy of Worldwalker Helm and a Map token
3. Activate Urza's first ability by tapping a Worldwaker Helm and a Map, adding
4. Activate a Worldwalker Helm by paying and tapping it, creating a token copy of the Worldwalker Helm token and a Map token for each Worldwalker Helm you control
5. Activate Urza's first ability twice by tapping two Maps, adding
6. Repeat from step 4

Results

• Infinite blue mana
• Exile your library
• Cast all cards in your library without paying their mana costs
• Infinite Map tokens