<script src="http://spelprogrammering.nu/simple.js">
function start()
{
  icbm = {sx: 0,
          sy: 0,
          v0: 100,
          alpha: pi/4};
  
  world = {g: -9.8,
           t: 0};
  
  icbm.v0x = icbm.v0 * cos(icbm.alpha);
  icbm.v0y = icbm.v0 * sin(icbm.alpha);
}

function update()
{
  world.t += 0.1;

  var prevX = icbm.sx;
  var prevY = icbm.sy;

  icbm.sy = totalHeight-(icbm.v0y*world.t + world.g*world.t*world.t/2);
  icbm.sx = icbm.v0x*world.t;

  var angle = atan((icbm.sy-prevY) / (icbm.sx-prevX)) * 180/pi;

  clearScreen();

  save();
  translate(icbm.sx, icbm.sy);
  rotate(angle);
  rectangle(0, 0, 40, 20, "silver");
  triangle(40, 0, 40, 20, 50, 10, "red");
  restore();
}
</script>