  Hex systems were recently introduced [A. P. Kels. Integrable systems on
hexagonal lattices and consistency on polytopes with quadrilateral and
hexagonal faces. 2022. arXiv:2205.02720 [math-ph]] as systems of equations
defined on two-dimensional honeycomb lattices. We give a definition of
algebraic entropy for such systems and use it to check the integrability of
specific examples.

Exactly Solvable and Integrable Systems