plot_parametric((2 * cos(t), sin(t)), (cos(t), 2 * sin(t)),
   (t, 0, 2*pi), use_cm=False)
# Expected:
## Plot object containing:
## [0]: parametric cartesian line: (2*cos(t), sin(t)) for t over (0.0, 6.283185307179586)
## [1]: parametric cartesian line: (cos(t), 2*sin(t)) for t over (0.0, 6.283185307179586)