docs: def mirror(ax, p0, alpha=0, size=2.54, width=0.5, format=None):
      r"""Draw a mirror."""
      if format is None: format = 'k-'
  
      x0 = [size/2, -size/2, -size/2, size/2, size/2]
      y0 = [0, 0, -width, -width, 0]
  
      x1 = [size/2, size/2-width]; y1 = [0, -width]
      x2 = [-size/2+width, -size/2]; y2 = [0, -width]
      x3 = [(size/2-size/2+width)/2, (size/2-width-size/2)/2]; y3 = [0, -width]
  
      cur_list = [(x0, y0), (x1, y1), (x2, y2), (x3, y3)]
      cur_list = rotate_and_traslate(cur_list, alpha, p0)
      for curi in cur_list: ax.plot(curi[0], curi[1], format)