Top-Secret Tunnel

While Contraptions you control are on the battlefield, the Contraption deck is not, even if you are using it to signify the three sprockets.

If you crank multiple Contraptions, their abilities can be put onto the stack in any order. The ability put onto the stack will resolve first.

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.

Contraptions are artifacts. Anything that interacts with artifacts will interact with Contraptions.

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

If you or a permanent you control are instructed to assemble a Contraption, reveal the top card of your Contraption deck. Put it onto the battlefield on one of the three sprockets.

If a Contraption would leave the battlefield and go to any zone other than exile, it instead goes to the scrapyard, the Contraption deck's version of the graveyard. Things that affect the graveyard do not affect the scrapyard. You can exile Contraptions just fine.