<script src="http://spelprogrammering.nu/simple.js">
function start() 
{
  translate(-35,-115);
  tank(10, 250, 1, "rgb(80, 100, 0)");
  tank(600, 250, -1, "rgb(120, 80, 0)");

  for (var x = 180; x <= 520; x += 20) 
  {
    var y = 120 + (x - 380) * (x - 380) / 350;
    circle(x, y, 3, "grey");
    if (x == 520)
      circle(x, y, 6, "red");
  }
}

function tank(x, y, dir, c) 
{
  rectangle(x + 50, y + 60, 100, 40, c);
  triangle(x + 50, y + 60, x + 25, y + 80, x + 50, y + 100, c);
  triangle(x + 150, y + 60, x + 175, y + 80, x + 150, y + 100, c);
  circle(x + 100, y + 75, 30, c);
  line(x + 100, y + 75, x + 100 + 50 * dir, y + 10, 8, c);
  circle(x + 60,  y + 100, 18, "black");
  circle(x + 100, y + 100, 18, "black");
  circle(x + 140, y + 100, 18, "black");
  circle(x + 60,  y + 100, 5, "grey");
  circle(x + 100, y + 100, 5, "grey");
  circle(x + 140, y + 100, 5, "grey");
}
</script>