load(draw);

a : [1,0];
b : [0,1];

O : [0,0];

len : 3;
mesh : [];
block([],
    for i : 0 thru len do (
      mesh : append (mesh, [points([O + i*a, O + i*a + len*b])]),
      mesh : append (mesh, [points([O + i*b, O + len*a + i*b])])
      )
    );


draw2d(
  xrange = [-1,4],
  yrange = [-1,4],
  xtics = false,
  ytics = false,

  head_length = 0.2,
  /* kreuz */
  vector(0+0.5*a+1.5*b, 3*a),
  vector(0+1.5*a+2.5*b, -3*b),
  /* Diagonalen */
  vector(0+0.5*a+2.5*b, 3*(a-b)),
  vector(0+2.5*a+2.5*b, 3*(-a-b)),
  label (["S", 1.5, -0.7]),
  label (["S", 3.8, 1.5]),
  label (["S", -0.5, -0.7]),
  label (["S", 3.5, -0.7]),

  point_type = none,
  line_width = 5,
  points_joined = true,
  mesh,

  file_name = "mag3mittlereselement",
  dimensions = [600,600],
  terminal = png
);