Physical Zero-Knowledge Proof For Makaro

Makaro is a logic game similar to Sudoku. In Makaro, a grid has to be filled with numbers such that: given areas contain all the numbers up to the number of cells in the area, no adjacent numbers are equal and some cells provide restrictions on the largest adjacent number. We propose a proven secure physical algorithm, only relying on cards, to realize a zero-knowledge proof of knowledge for Makaro. It allows a player to show that he knows a solution without revealing it.