Quadrifolium
The quadrifolium is a type of rose curve with n=2. It has the polar equation:
with corresponding algebraic equation
Rotated by 45°, this becomes
with corresponding algebraic equation
In either form, it is a plane algebraic curve of genus zero.
The dual curve to the quadrifolium is
The area inside the curve is, which is exactly half of the area of the circumcircle of the quadrifolium. The length of the curve is about 9.6884.
