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Jackson was big dancer, however, he needed some apparatus for perfect dancing; you can see below the patented apparatus ;
https://www.google.com/patents/US5255452
Briefly,
A system for allowing a shoe wearer to lean forwardly beyond his center of gravity by virtue of wearing a specially designed pair of shoes which will engage with a hitch member movably projectable through a stage surface. The shoes have a specially designed heel slot which can be detachably engaged with the hitch member by simply sliding the shoe wearer's foot forward, thereby engaging with the hitch member.