Question: Who designed the earlier ride that was modified to become the Gravitron?

Context paragraphs:
King Cobra (roller coaster): King Cobra (1984–2001) was a TOGO Stand-up roller coaster located at Kings Island in Mason, Ohio.  It was the first in the world to be designed from the ground up as a stand-up roller coaster.  Other stand-up roller coasters that preceded King Cobra were sit-down models later modified to accommodate stand-up trains.  After the ride's manufacturer, TOGO, went out of business in 2001, parts for the ride became more expensive and harder to find.  In addition, the ride was losing popularity in recent years.  So in April 2002, Paramount Parks decided to dismantle King Cobra and put it up for sale.  Trains were sent to Kings Island's "graveyard" located at the old Wild Animal Habitat feeding house area next to the Son of Beast.  After the ride wouldn't sell, the decision was made in 2008 to transfer some of the ride including the trains to Kings Dominion to be used as spare parts for Shockwave.  As of 2010, remnants of the King Cobra can still be spotted in some back areas of Kings Island near Flight of Fear

Ranger (ride): A Ranger is an inverting pendulum ride first manufactured by HUSS Machinenfabrik in 1981.  Many of the design elements were later used in the HUSS Rainbow, and the term 'Ranger' has become synonymous with inverting pendulum rides.  It was the first inverting swing ride designed since Lee Eyerly's Loop-O-Plane and set the standard for many other attractions using the inverting pendulum ride system, such as the Rainbow, the Kamikaze (ride), and the Inverter.

Touring bicycle: A touring bicycle is a bicycle designed or modified to handle bicycle touring.  To make the bikes sufficiently robust, comfortable and capable of carrying heavy loads, special features may include a long wheelbase (for ride comfort and to avoid pedal-to-luggage conflicts), frame materials that favor flexibility over rigidity (for ride comfort -- though frame flexing can eventually lead to metal fatigue and frame failure, so newer frames are rigid), heavy duty wheels (for load capacity), and multiple mounting points (for luggage racks, fenders, and bottle cages).

Turbo Mountain: Turbo Mountain was a steel roller coaster at Adventure World in Perth, Western Australia, Australia.  The ride was closed and removed in 2009 to make room for a HUSS Shot'N Drop tower named Freefall.  The ride was originally located in Luna Park Sydney as a standard Schwarzkopf Jet Star 2 bought second hand.  When the ride was moved to "Adventure World" in 1991, the ride's lift hill was modified from a spiral lift hill to a standard chain lift hill due to maintenance.

Tower of Terror II: The Tower of Terror II is a steel shuttle roller coaster located at the Dreamworld amusement park on the Gold Coast, Queensland, Australia.  When the Tower of Terror opened on 23 January 1997, it was the first roller coaster in the world to reach 160.9 km/h speeds making it the tallest and fastest roller coaster in the world of its time.  The ride is situated on the Dreamworld Tower which also houses The Giant Drop free fall ride.  The ride was originally known as the "Tower of Terror" until it was modified and relaunched in September 2010.

Rotor (ride): The Rotor is an amusement park ride, designed by German engineer Ernst Hoffmeister in the late 1940s.  The ride was first demonstrated at Oktoberfest 1949, and was exhibited at fairs and events throughout Europe during the 1950s and 1960s.  The ride still appears in numerous amusement parks, although travelling variants have been surpassed by the Gravitron.

Knott's Bear-y Tale: Knott's Bear-y Tales was a dark ride located at Knott's Berry Farm that opened in 1975 as part of the Roaring 20s area.  The attraction was designed by Disney Imagineer Rolly Crump as part of creating a ride that would compliment the former area of the park known as Gypsy Camp.  However, the dwindling Gypsy Camp would end up becoming a new section called the Roaring 20s (now known as The Boardwalk).  As a result, the design of Bear-y Tales was altered two times until it ended up reflecting the theme of the Roaring 20s area.  During construction, the building was caught on fire and a couple of scenes that were under development were destroyed.  However, the attraction was given an extended deadline to allow more time and reconstruction of the damaged parts of the ride.  In the fall of 1986, Knott's Bear-y Tales was closed to become Kingdom of the Dinosaurs due to the then upcoming trend of Dinosaurs.  Following the closure, Many of the animatronics and set pieces were obtained by employees, while others stayed within Knott's to become a part of a walk-through experience in 1987 located at the Camp Snoopy area.  That attraction also closed and was removed in 1997.

Gravitron: The Gravitron (also known as the Starship, Starship 2000, Starship 3000, Starship 4000, Starship Area 51, Starship Gravitron, Starship Exodus, Alien Abduction, Alien Invasion, Twister, Devil's Hole, Area 51, and Enterprise) is an amusement ride, most commonly found as a portable ride at fairs and carnivals.  The Gravitron first appeared at Morey's Piers in 1983 and quickly became a fixture at amusement parks in many countries.  It is a modification of an earlier ride called the Rotor.  The ride was originally designed and manufactured by Wisdom Industries, though several examples of the Gravitron were produced under license by ARM in the UK and Ferrari in Australia.

Screamin' Eagle: The Screamin' Eagle is a wooden roller coaster at Six Flags St. Louis.  When it opened in 1976 for America's Bicentennial celebration, Guinness World Records listed it as the largest coaster at 110 ft high and as the fastest coaster at 62 mi/h .  The ride is a modified 'L'-Shaped Out And Back.  The Screamin' Eagle was manufactured by the Philadelphia Toboggan Coasters and was the last coaster designed by the renowned John Allen, who was a historic designer of roller coasters.  Allen believed a coaster should inspire awe, not only from a ride full of thrills, but also from its magnificent beauty.  Originally Allen wanted to design a coaster to replace the Comet at Chain of Rocks Amusement Park, but lack of funds prevented him from doing such.  The Screamin' Eagle is reminiscent of the Comet, mirroring its L-shape, but to a much larger scale.

Firefall (ride): Firefall was a Top Spin located at California's Great America.  Manufactured by HUSS Park Attractions, the ride was originally located at Geauga Lake under the name Texas Twister.  It was the first of its kind in North America.  Upon the park's closing, the ride was relocated to its sister park, California's Great America, where it reopened in 2008.  When it was moved, its original ride program was slightly modified.

Supporting paragraphs: Gravitron Rotor (ride)
Answer: Ernst Hoffmeister