#include "common.h"

bool tile_empty(tile_t t);
index_t abs_pos(index_t p);
index_t column(index_t i);
index_t row(index_t i);
tile_t  abs_tile(tile_t t);
bool same_color(tile_t a, tile_t b);
bool opposite_color(tile_t a, tile_t b);