Ancient engineers were able to build remarkable structures even though the raw materials and tools with which they could work were often limited. The Egyptian pyramids, for example, were built of multiton stone blocks using only the fulcrum and lever, wedge, ramp, sledge, and rollers. The pyramid builders of 2600 B.C. used tools made only of wood and copper. Advances in engineering were slow and based primarily on practical experience until advances in mathematics, especially from the Greeks, led to the new experimentation and techniques.