Arms Depot

At the beginning of your upkeep, if you control any Contraptions, move the CRANK! counter to the next sprocket. You may then crank any number of Contraptions on that sprocket, causing their abilities to trigger. Cranking a Contraption is always optional.

Any Contraption that's on the battlefield and wasn't assembled immediately heads to the scrapyard. However, if it's a not an actual Contraption card (like Copy Artifact isn't), it goes to your graveyard as normal. Non-Contraption cards can't be in the scrapyard.

In Constructed formats, a Contraption deck must have at least fifteen different Contraption cards and no more than one of each.