a, b, n = 2, 1, 4
p, r, s = symbols("p r s")
xp = a * cos(p) * cos(n * p)
yp = a * sin(p) * cos(n * p)
zp = b * cos(n * p)**2 + pi
xr = root(r, 3) * cos(r)
yr = root(r, 3) * sin(r)
zr = 0
plot3d_parametric_line(
    (xp, yp, zp, (p, 0, pi if n % 2 == 1 else 2 * pi), "petals"),
    (xr, yr, zr, (r, 0, 6*pi), "roots"),
    (-sin(s)/3, 0, s, (s, 0, pi), "stem"), use_cm=False)
# Expected:
## Plot object containing:
## [0]: 3D parametric cartesian line: (2*cos(p)*cos(4*p), 2*sin(p)*cos(4*p), cos(4*p)**2 + pi) for p over (0.0, 6.283185307179586)
## [1]: 3D parametric cartesian line: (r**(1/3)*cos(r), r**(1/3)*sin(r), 0) for r over (0.0, 18.84955592153876)
## [2]: 3D parametric cartesian line: (-sin(s)/3, 0, s) for s over (0.0, 3.141592653589793)