Problem: Background: Robert Gordon Orr, OC (born March 20, 1948) is a Canadian former professional ice hockey player, widely acknowledged as one of the greatest hockey players of all time. Orr used his ice skating speed, scoring, and play-making abilities to revolutionize the position of defenceman. He played in the National Hockey League (NHL) for 12 seasons, starting with 10 with the Boston Bruins followed by two with the Chicago Black Hawks. Orr remains the only defenceman to have won the league scoring title with two Art Ross Trophies.
Context: Orr joined the Bruins for the 1966-67 season, his first as a professional. The Bruins were not convinced Orr belonged on defence, trying him out at centre first. Through the pre-season, Orr was given jersey number 27. At the season's start, the Bruins offered him jersey number 5, that of past Bruins star Dit Clapper, but Orr chose jersey number 4. Orr made his NHL regular-season debut on October 19, 1966, against the Detroit Red Wings, getting one assist. On October 22, he scored his first NHL goal against the Montreal Canadiens. It was a slap shot past Gump Worsley and the Boston Garden crowd gave Orr a standing ovation.  In that first season, Orr was challenged by the veterans, and he earned respect by defeating Montreal tough guy Ted Harris in his first NHL fight. On December 4, 1966, Toronto Maple Leafs' defenceman Marcel Pronovost checked him into the boards, injuring Orr's knees for the first time in the NHL. He would miss nine games and the Bruins would lose six of them. The team finished with a 17-43-10 record, leaving the Bruins in last place. However, attendance at Boston Garden increased by forty-one thousand fans.  For the season, Orr scored 13 goals and 28 assists, one of the best rookie seasons in NHL history to that point by a defenceman. Orr won the Calder Memorial Trophy as the league's outstanding rookie and was named to the NHL's Second All-Star team. New York Rangers defenceman Harry Howell won the Norris Trophy as the league's best defenceman that year. In accepting the award, Howell said he was glad to win when he did, predicting "Orr will own this trophy from now on." Orr was runner-up in voting.
Question: Was this the first time
Answer: injuring Orr's knees for the first time in the NHL. He would miss nine games and the Bruins would lose six of them.

Problem: Background: Zhang Heng (Chinese: Zhang Heng ; AD 78-139), formerly romanized as Chang Heng, was a Han Chinese polymath from Nanyang who lived during the Han dynasty. Educated in the capital cities of Luoyang and Chang'an, he achieved success as an astronomer, mathematician, scientist, engineer, inventor, geographer, cartographer, artist, poet, statesman, and literary scholar. Zhang Heng began his career as a minor civil servant in Nanyang. Eventually, he became Chief Astronomer, Prefect of the Majors for Official Carriages, and then Palace Attendant at the imperial court.
Context: Zhang Heng is often credited with inventing the first odometer, an achievement also attributed to Archimedes (c. 287-212 BC) and Heron of Alexandria (fl. AD 10-70). Similar devices were used by the Roman and Han-Chinese empires at about the same period. By the 3rd century, the Chinese had termed the device the ji li gu che, or "li-recording drum carriage" (the modern measurement of li = 500 m/1640 ft).  Ancient Chinese texts describe the mechanical carriage's functions; after one li was traversed, a mechanically driven wooden figure struck a drum, and after ten li had been covered, another wooden figure struck a gong or a bell with its mechanically operated arm. However, there is evidence to suggest that the invention of the odometer was a gradual process in Han Dynasty China that centered on the "huang men"--court people (i.e. eunuchs, palace officials, attendants and familiars, actors, acrobats, etc.) who followed the musical procession of the royal "drum-chariot". There is speculation that at some time during the 1st century BC the beating of drums and gongs was mechanically driven by the rotation of the road wheels. This might have actually been the design of Luoxia Hong (c. 110 BC), yet by at least 125 the mechanical odometer carriage was already known, as it was depicted in a mural of the Xiao Tang Shan Tomb.  The south-pointing chariot was another mechanical device credited to Zhang Heng. It was a non-magnetic compass vehicle in the form of a two-wheeled chariot. Differential gears driven by the chariot's wheels allowed a wooden figurine (in the shape of a Chinese state minister) to constantly point to the south, hence its name. The Song Shu (c. AD 500 ) records that Zhang Heng re-invented it from a model used in the Zhou Dynasty era, but the violent collapse of the Han Dynasty unfortunately did not allow it to be preserved. Whether Zhang Heng invented it or not, Ma Jun (200-265) succeeded in creating the chariot in the following century.
Question: Did any one aid him on its construction?
Answer:
Whether Zhang Heng invented it or not, Ma Jun (200-265) succeeded in creating the chariot in the following century.