var py = 0;

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(200);

​

  var A = 0.965;

  var B = 1.0 - A; 

  var targetX = mouseX; 

  var targetY = mouseY; 

  var qx = px; // stash previous values. 

  var qy = py; 

  px = A*px + B*targetX;

  py = A*py + B*targetY;

  var dx = px - qx; 

  var dy = py - qy;

  var orientation = atan2(dy, dx);  

  push();

  rectMode(CENTER); 

  translate(px, py); 

  rotate(orientation); 

  rect(0,0, 40, 40);

  ellipse(20,-20, 20,20); 

  ellipse(20,20, 20,20); 

  pop(); 

}