constructor(x, y, len){

    this.pos = createVector();

    this.color = color("rgba(138, 76, 15, 0.5)");

​

    this.root = createVector(x, y);

​

    //spring constants

    this.angle = 10;

    this.angleV = 0;

    this.angleA = 0;

    this.len = len;

    this.gravity = 0.9;

  }

  show(){

    push();

    strokeWeight(4);

    stroke(this.color);

    line(this.root.x, this.root.y, this.pos.x, this.pos.y);

    pop(); 

​

  }

  update(){ 

    // pendulum logic

    let an = map(angle, -60, 60, 110, -110)

    let force = this.gravity * sin(this.angle+an);

    this.angleA = (-1 * force) / (this.len/4);

    this.angleV += this.angleA;

    this.angle += this.angleV;

    this.angleV *= 0.99; // slow it down over time

​

    this.pos.x = this.len * sin(this.angle) + this.root.x;

    this.pos.y = this.len * cos(this.angle) + this.root.y; 

  }

}