torsion box ski construction design is patented. The patent is referenced by Kästle, Salomon, Rottefella, and Madshus. In 1993 Elan introduced the Elan SCX model, skis with a much wider tip and tail than waist. When tipped onto their edges, they bend into a curved shape and carve a turn. Cross-country techniques use different styles of turns; edging is not as important, and skis have little sidecut. For many years, alpine skis were shaped similarly to cross-country, simply shorter and wider, but the Elan SCX introduced a radial sidecut design that dramatically improved performance. Other companies quickly followed suit, one Austrian ski designer admitting, "It turns out that everything we thought we knew for forty years was wrong." Line Skis, the first free-ski focused ski company inspired the newschool freeskiing movement with its twin-tip ski boards in 1995. The first company to successfully market and mass-produce a twin-tip ski to ski switch (skiing backwards) was the Salomon Group, with its 1080 ski in 1998. Geometry Described in the direction of travel, the front of the ski, typically pointed or rounded, is the tip, the middle is the waist and the rear is the tail. Skis have four aspects that define their basic performance: length, width, sidecut and camber. Skis also differ in more minor ways to address certain niche roles. For instance, mogul skis are softer to absorb shocks, powder skis are wider to provide more float and rocker skis bent upwards (reverse camber) at the tip and tail to make it easier to turn in deep and heavy snow. Construction Skis have evolved from being made of solid wood to using a variety of materials including carbon-Kevlar to make skis stronger, stiffer in twisting, lighter, and more durable. Ski manufacturing techniques allow skis to be made in one or a combination of three designs: Laminate or sandwich Laminated skis are built in layers. Materials such as fiberglass, steel, aluminum alloy, or plastic are layered and compressed above and below the core. Laminated construction is the most widely used manufacturing process in the ski industry today. The first successful laminate ski, and arguably the first modern ski was the Head Standard, introduced in 1950, which sandwiched aluminum alloy around a plywood core. Torsion box The Dynamic VR7 introduced a new construction method in which a smaller wooden core was wrapped in wet fibreglass, as opposed to pre-dried sheets of fibreglass