Ingenuity Engine

Ingenuity Engine can be the target of its own ability. It can be artifact you sacrifice as part of the activation cost. It can even be both, although that will result only in you sacrificing Ingenuity Engine and not returning anything to its owner's hand.

The mana value of a split card is determined by the combined mana cost of its two halves. If cascade allows you to cast a split card, you may cast either half but not both halves.

Due to a 2021 rules change to cascade, not only do you stop exiling cards if you exile a nonland card with lesser mana value than the spell with cascade, but the resulting spell you cast must also have lesser mana value. Previously, in cases where a card's mana value differed from the resulting spell, such as with some modal double-faced cards or cards with an Adventure, you could cast a spell with a higher mana value than the exiled card.