use use size = [50, 25]; tile_width = 5; line_width = 1; for(tile = tile_truchet(size)) { x = tile.x; y = tile.y; if(tile[2] <= 1) { line2d([x, y] * tile_width , [x + 1, y + 1] * tile_width, width = line_width); } else { line2d([x + 1, y] * tile_width, [x, y + 1] * tile_width, width = line_width); } }