Implementation of the Hydra Game described in the paper Accessible independence results for Peano Arithmetic by L. Kirby and J. Paris. A good explanation of the rules can be found here.
Use leftclick to select a node to chop off, scroll to zoom in or out, and
leftclick+drag to translate the picture.
Install Haskell's tool Stack. Then, inside the repo's main folder run
stack setup
stack build
stack exec hydra