In the 1950s, forestry engineer Norman Franz experimented with an early form of water jet cutter to cut lumber. However, the technology did not advance notably until the 1970-80s when Mohamed Hashish added abrasives to the water. This and other concepts allowed Yih-Ho Michael Pao to develop commercial "ultrahigh-pressure water-jets and abrasive-waterjets into better tools for industrial cutting, drilling, and milling, especially for the flexible factory automation." Today the water jet is unparalleled in many aspects of cutting and has changed the way many products are manufactured. Many types of water jets exist today, including pure water jets(water only), abrasive water jets, percussive water jets, cavitation jets and hybrid jets.