khozlee

n geometry, a Devil's curve is a curve defined in the Cartesian plane by an equation of the form
y2(y2 a2) = x2(x2 b2).
Devil's curves were studied heavily by Gabriel Cramer. The name comes from the shape it takes when graphed.
It seems that the devil in the name of the curve is from a juggling game called diabolo, which involves two sticks, a string, and a spinning prop in the likeness of the form of this curve. The confusion is the result of the Italian word diabolo meaning 'devil'.