My studies lead me to the following parametrization of perhaps a new class of plane curves ( which are similar in shape to the classical sinusoidal spirals but not identical ). If the curves are not yet known I humbly dare to call them $T$-curves.
\begin{align} &x(t)= \cos t + \cos \left(\frac{n+1}{n-1} t \right), \\ &y(t)=-\sin t + \sin \left(\frac{n+1}{n-1} t \right). \end{align}
As you see there is a connection to Chebyshev polynomials of the first and second kind.
If you plot for odd values of $n>1$ the graph shows spirals with $n$ sheets as expected. But if you plot for even values $n \geq 2$ the graph shows strangely $2n$ leafs. ( the parameter domain is $0$ to $2 (n-1) \pi$ )
For e.g. $n=2$ I would have liked to see the Bernoulli lemniscate.
Q1 : is there a parametrization which ideally would resulting correctly in $n$ leafs for all values of $n$ (perhaps only $n \geq 3$)?
Q2 : how to tackle the problem whether these $T$-curves are algebraic (as the classical sinusoidal spirals are)?
Edit to correct a previous faulty version. These curves are related to special cases of epicycloids for the special case $R=1$