let y1, y2;

let px2, py2;

let g = 1;

let angle1;

let angle2;

let angle1_v = 0;

let angle2_v = 0;

​

let r1 = 100;

let r2 = 100;

let m1 = 20;

let m2 = 20;

​

let trail;

​

function setup() {

  createCanvas(400, 400);

  trail = createGraphics(400,400);

  trail.background(220);

  trail.pixelDensity(1);

  angle1 = PI/2;

  angle2 = -PI/4;

  // x1 = 0;

  // y1 = 0;

  // x2 = 0;

  // y2 = 0;

}

​

function draw() {

  background(220);

  image(trail,0,0);

  translate(200, 10);

  trail.line(x2+200,y2+10,px2+200,py2+10);

  px2 = x2;

  py2 = y2;

​

​

  x1 = r1 * sin(angle1);

  y1 = r1 * cos(angle1);

​

  x2 = x1 + r2 * sin(angle2);

  y2 = y1 + r2 * cos(angle2);

​

  let num1 = -g * (2 * m1 + m2) * sin(angle1);

  let num2 = -m2 * g * sin(angle1 - 2 * angle2);

  let num3 = -2 * sin(angle1 - angle2) * m2 * (angle2_v * angle2_v * r2 + angle1_v * angle1_v * r1 * cos(angle1 - angle2));

  let dem = r1 * (2 * m1 + m2 - m2 * cos(2 * angle1 - 2 * angle2));

  let angle1_a = (num1 + num2 + num3) / dem;

​

  num1 = 2 * sin(angle1-angle2) 

  num2 = (angle1_v*angle1_v* r1*(m1+m2) + g * (m1+m2)*cos(angle1)+angle2_v*angle2_v*r2*m2*cos(angle1-angle2));

  dem = r2 * (2 * m1 + m2 - m2 * cos(2 * angle1 - 2 * angle2));

  let angle2_a = (num1*num2)/dem;

​

  angle1_v += angle1_a;

  angle2_v += angle2_a;

  angle1 += angle1_v;

  angle2 += angle2_v;

​

  stroke(0);

  line(0, 0, x1, y1);

  line(x1, y1, x2, y2);

  ellipse(x1, y1, 16);

  ellipse(x2, y2, 16);

​

}