children to develop creativity and problem-solving abilities. Teachers had been using Lego bricks in the classroom for a variety of reasons. In 1980, the Lego Group established the Educational Products Department (eventually renamed Lego Dacta, in 1989), to expand the educational possibilities of their toys. A packing and assembly factory opened in Switzerland, followed by another in Jutland, Denmark, that manufactured Lego tyres. Between the 1960s and '90s, Lego worked with Royal Dutch Shell in allowing Shell branding on certain items. In 1981, the second generation of Lego trains appeared. As before, these were available in either 4.5 V (battery-powered) or 12 V (mains powered), but with a much wider variety of accessories, including working lights, remote-controlled points and signals, and decouplers. The "Expert Builder" series matured in 1982, becoming the "Technic" series. 13 August of that year marked the Lego Group's 50th anniversary; the book 50 Years of Play was published to commemorate the occasion. In the following year, the Duplo system was expanded to include sets for even younger audiences, particularly infants; new sets included baby rattles and figures with movable limbs. The year after, Lego minifigure citizens gained a realm of knights and horses, with a redesign of the Castle theme. Light & Sound sets made their appearance in 1985; these sets included a battery pack with electrical lights, buzzers, and other accessories to add another dimension of realism to Lego creations. Also, that year, the Lego Group's educational division produced the Technic Computer Control, which was an educational system whereby Technic robots, trucks, and other motorized models could be controlled with a computer. Manaus, Brazil gained a Lego factory in this year, as well. In 1984, the Technic line was expanded with the addition of pneumatic components. In August 1988, 38 children from 17 countries took part in the first Lego World Cup building contest, held in Billund. That same year, Lego Canada was established. The Lego line grew again in 1989 with the release of the Lego Pirates theme, which featured a variety of pirate ships, deserted islands, and treasure. The Lego Group's Educational Products Department was renamed Lego Dakta in this year; the name comes from the Greek word "didactic," which roughly means "the study of the learning process." MIT's Dr. Seymour Papert, from the Laboratory of Computer Learning, was named "Lego Professor of Learning Research," after his ongoing work in linking the Logo