<script src="http://spelprogrammering.nu/simple.js">
function start()
{
  math.DDDPerspective = false;
  math.rotate3D(0.2,-0.1,0);
  math.axes3D();

  a     = {x: 1, y: 0, z: -3};
  b     = {x: 3, y: 2, z: -1};

  math.line3D(a.x, a.y, a.z,  b.x, b.y, b.z, "blue");

  math.point3D(a.x, a.y, a.z, "green");
  math.text3D(a.x-0.35, -0.1, -3.5, "p1", "green");

  math.point3D(b.x, b.y, b.z, "red");
  math.text3D(b.x-0.65, 1.5, -3.5, "p2", "red");

  math.text3D(1.6, 0.65, -3.5, "c", "blue");

  math.text3D(-3, 2,   -3.5, "p1 = (1,0,-3)", "green");
  math.text3D(-3, 1.5, -3.5, "p2 = (3,2,-1)", "red");
  math.text3D(-3, 1,   -3.5, "c = ?", "blue");
}
</script>