Once upon a time a certain tradesman was leading a caravan to another country to sell his goods. Along the way they came to the edge of a severe hot-sand desert. They asked about, and found that during the day time the sun heats up the fine sand until it ' s as hot as charcoal, so no one can walk on it - not even bullocks or camels! So the caravan leader hired a desert guide, one who could follow the stars, so they could travel only at night when the sand cools down. They began the dangerous night time journey across the desert. A couple nights later, after eating their evening meal, and waiting for the sand to cool, they started out again. Later that night the desert guide, who was driving the first cart, saw from the stars that they were getting close to the other side of the desert.