# What is a quadrifolium?

$r = a \sin \left(2 \theta\right)$
For $a = 1$, the graph looks like this:
An interesting fact about a quadrifolium is that if you were to draw a circle around the rose curve, the area inside the rose curve would be exactly half the area of the entire circle, $\frac{1}{2} \pi {a}^{2}$