Cissoid
Cissoid. History. Diocles ( 250 – 100 BC) invented this curve to solve the dou ... This will give us an equation for the. Cissoid in polar coordinates (r, θ) ...
http://xahlee.org/SpecialPlaneCurves_dir/CissoidOfDiocles_dir/cissoid_of_Diocles.pdf