Grindstone and Sun/Moon Wheel

[OffTheWall]

If a player has a Sun/moon wheel (Shadowmoor) enchanting themselves, and their opponent Grindstones them with a painter's servant in play. What happens when the grindstone is activated? The Sun/moon wheel is a replacement effect, but does the grindstone activate more than once?

[Nihil Credo]

Replacement effect do just that, they replace things. Therefore, the Grindstone activation would work like "Put the top two cards of target player’s library on the bottom of that player's library. If both cards share a color, repeat this process.". With a Painter's Servant in play, that process will go on forever and bring the game to a draw.