Painter's Servant, and Grindstone

Prerequisites

• All permanents on the battlefield
• Painter's Servant can be naming any color
• available

Steps

1. Activate Grindstone by paying and tapping it, causing target player to mill two cards
2. Because both cards will share a color due to Painter's Servant, the process in step 1 repeats until the player has milled their entire library

Results

• Infinite mill for target player