A SuperEllipse is a curve with (Cartesian) equation:

   |(x/a)|^r + |(y/b)|^r = 1
A SuperEllipse can also be described as:

   x  =  a cos^(2/r) t  =  a (cos t)^(2/r)
   y  =  b cos^(2/r) t  =  b (cos t)^(2/r)

PietHein called the curve with r = 5/2 and a = b "the" superellipse.

See also: 
*** http://mathworld.wolfram.com/Superellipse.html
***http://www.2dcurves.com/power/powerse.html

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CategoryMath