Quadrifolium

The quadrifolium (also known as four-leaved clover[1]) is a type of rose curve with an angular frequency of 2.

It has the polar equation: with corresponding algebraic equation Rotated counter-clockwise by 45°, this becomes with corresponding algebraic equation In either form, it is a plane algebraic curve of genus zero.

, which is exactly half of the area of the circumcircle of the quadrifolium.

is the complete elliptic integral of the second kind with modulus

denotes the derivative with respect to the second variable.