docs: def simple_beam_splitter(ax, p0, size=2.54, width=0.1, alpha=0,
                           format=None, **kwds):
      r"""Draw a simple beam splitter."""
      if format is None: format = 'k-'
      a = size/2
      b = width/2
      x0 = [a, -a, -a, a, a]
      y0 = [b, b, -b, -b, b]
  
      cur_list = [(x0, y0)]
      cur_list = rotate_and_traslate(cur_list, alpha, p0)
  
      for curi in cur_list: ax.plot(curi[0], curi[1], format, **kwds)