Answer:
limaçon (no inner loop)
Explanation:
The equation of a limaçon is written generically as ...
r = b + a·cos(θ)
For b=2 and a=1, this would put the flat side on the left. Rotating it 180° can be accomplished by adding or subtracting π from θ. Then the equation can be ...
r = 2 + cos(θ-π) . . . . or ...
r = 2 - cos(θ)