Ancient Egyptian technology describes devices and technologies invented or used in Ancient Egypt. The Egyptians invented and used many simple machines, such as the ramp and the lever, to aid construction processes. They used rope trusses to stiffen the beam of ships. Egyptian paper, made from papyrus, and pottery were mass-produced and exported throughout the Mediterranean Basin. The wheel was used for a number of purposes, but chariots only came into use after the Second Intermediate Period. The Egyptians also played an important role in developing Mediterranean maritime technology including ships and lighthouses. Significant advances in ancient Egypt during the dynastic period include astronomy, mathematics, and medicine. Their geometry was a necessary outgrowth of surveying to preserve the layout and ownership of fertile farmland, which was flooded annually by the Nile River. The 3,4,5 right triangle and other rules of thumb served to represent rectilinear structures, and the post and lintel architecture of Egypt. Egypt also was a center of alchemy research for much of the western world. The word paper comes from the Greek term for the ancient Egyptian writing material called papyrus, which was formed from beaten strips of papyrus plants. Papyrus was produced in Egypt as early as 3000 BC and was sold to ancient Greece and Rome. The establishment of the Library of Alexandria limited the supply of papyrus for others. According to the Roman historian Pliny the Elder (Natural History records, xiii.21), as a result of this, parchment was invented under the patronage of Eumenes II of Pergamon to build his rival library at Pergamon. However, this is a myth; parchment had been in use in Anatolia and elsewhere long before the rise of Pergamon. Egyptian hieroglyphs, a phonetic writing system, served as the basis for the Phoenician alphabet from which later alphabets, such as Hebrew, Greek, and Latin were derived. With this ability, writing and record-keeping, the Egyptians developed one of the – if not the – first decimal system.