My answer got lost too. I would advise to use the graphics primitives, such as Line, instead of ParametricPlot when you are simply drawing a few straight lines. ParametricPlot is for curves. Your code would also be cleaner.

Oh I got It, but as I see I can't have something like the image below. For something like the image should I realize another quadrilateral liked to the other one or is the a faster solution?

You can do it by showing your plot together with a Scaled version:

With[
 {ruotaSinistra =
   Show[(*Plot Traiettoria Nera*)
    ParametricPlot[
     Quadrilatero[qq, xA, yA, Lc, L2, L3, modo, xD, 
        yD][[3]][[2]], {qq, 0, q + 0.00001}, 
     PlotRange -> {{-1, 1}, {-.2, .4}}, AspectRatio -> .5, 
     PlotStyle -> {Black, Dashed}]
    (*etc*)]}, 
 Show[ruotaSinistra, 
  Graphics[Scale[ruotaSinistra[[1]], {-1, 1}, {0, 0}]]]]

Replace the (*etc*) with the rest of your plot.