  In the context of interactive proofs, a "folding scheme" (popularized by
Nova) is a way to combine multiple instances of a constraint system into a
single instance, so the validity of the multiple instances can statistically be
reduced to the validity of a single one. We show how Nova folding can be
generalized to ``custom'' gates and extra rounds of verifier randomness. As an
application of this extension, we present Origami, the first (to our knowledge)
known example of a folding scheme for lookups.
