Plonky

Plonky is a prototype implementation of recursive arguments. It is loosely based on PLONK, with a few customizations:

While PLONK uses KZG's pairing-based polynomial commitment scheme, we use a batched variant of the Halo technique to recursively verify discrete log based polynomial commitments.
The standard PLONK model was designed for arithmetic circuits; it uses a single constraint to verify additive and multiplicative relationships. We use a variety of custom gates, such as a gate which performs a step of a Rescue permutation. The maximum degree of our constraints is 8, compared to 3 in standard PLONK.
In standard PLONK, each gate interacts with three wires, which are typically thought of as two input wires and one output wire. We use a much higher arity -- 9 wires per gate -- although only 6 of them are involved in the permutation argument. The other 3 can be thought of as "advice" wires.
The zero-knowledge technique in the Plonk paper would cause each witness polynomial's degree to slightly exceed a power of two, which doesn't work well with Halo. We use a different blinding method.

Disclaimer

This code has not been thoroughly reviewed or tested, and should not be used in any production systems.