Meanest Machine-This huge tree-crusher can clear an acre of unproductive forest in 15 minutes. Designed and built by R. G. LeTourneau, Inc., of Longview, Tex., the brutal combination of mass and power can chew its way through a forest, ripping trees up by the roots, slapping them to the ground and finally smashing them to splinters for thorough burning. The monster is 75 feet long, 22 feet wide and 19 feet high. It weighs 150 tons. The maker believes it will be extremely useful clearing jungle in places such as Africa and South America. The machine costs almost $200,000.