function walkThroughWall (R)
    if ~R.is_bord('n')
        R.step('n')
    else
        length = 1;
        Door = 0;
        direction = 'w';
        while ~Door
            Door = move(R, direction, length);
            direction = changeDirection(direction);
            length++;
        end
    end
end

function Door = stepAndFind (R, direction)
    R.step(direction)
    Door = ~R.is_bord('n');
end

function Door = move (R, direction, steps)
    flag = 0;
    for i = [1:steps]
        if stepAndFind(R, direction) && ~flag
            R.step('n');
            flag = 1;
        end
    end
    Door = flag;
end

function Direction = changeDirection (direction)
    if direction == 'o'
        Direction = 'w';
    else
        Direction = 'o';
    end
end