Rails on Tiles（どう書く） - Qiita

module RailsOnTiles Tiles = [[2, 3, 0, 1], [1, 0, 3, 2], [3, 2, 1, 0]] Dirs = [[0, -1], [1, 0], [0, 1], [-1, 0]] module_function def go(input) field = input.chars.map(&:to_i).each_slice(3).to_a solve(field).map { |i| ("A".."I").to_a[i] }.join end def solve(field, x=1, y=-1, dir=2, route=[]) dx, dy = Dirs[dir] x += dx y += dy return route if x < 0 || x > 2 || y < 0 || y > 2 rev = Tiles[0][dir] nxt