To those who dare to take a walk through the local valleys and meadows every once in a while they see a familiar sight: artistically crafted walls that line the sides of many paths - made entirely with stones and without the use of any other means. A few decades ago people used to build walls, stairs, terraces, and even whole houses with stones from the immediate surroundings, most of the time without even using mortar. With Build a wall, everybody can try to build their own straight wall using stones that are not of exact geometrical shape. That's not easy. Next time you go for a wall you'll surely be looking at the old walls with different eyes.