Noncreature Artifact with MV<=1 in your graveyard.
All other permanents on the battlefield.
Easy Prerequisites
You have not cast an artifact spell using
Muldrotha this turn.
Mana Needed
({1} magic symbol) at most available.
Steps
Cast the artifact from your graveyard by paying ({0} magic symbol) .
Displacer Kitten and
Kykar trigger.
Resolve the
Displacer Kitten trigger, blinking
Muldrotha.
Resolve the
Kykar trigger, creating a 1/1 Spirit creature token.
When the artifact enters,
Grinding Station triggers, untapping
Grinding Station.
Activate
Kykar by sacrificing the Spirit, adding ({R} magic symbol) .
Activate
Grinding Station by tapping it and sacrificing the artifact.
Repeat.
Notes
If the chosen artifact can tap to provide additional effects, you will also gain infinite amounts of those effects. For example, Sol Ring will give infinite colorless mana, and Codex Shredder will provide infinite mill and self-mill.