Recaman's sequence, old one

code.pde

//MODIFICATION//

let gap = 10;
let w = 29;

////////////////
let seq = [1,2,2];
let index = 2;

let circleCount = [0,0,1];
let oneCount = 1;
let twoCount = 2;

let lines = [];

function setup() {
  createCanvas(windowWidth, windowHeight);
  background(0);
}

class Lines {
  constructor(x1, y1, x2, y2) {
    this.x1 = x1;
    this.y1 = y1;
    this.x2 = x2;
    this.y2 = y2;
  }
  
  show() {
    line(this.x1,this.y1,this.x2,this.y2);
  }
}

function draw() {
  background(0,25);
  translate(width/2+(index%20-9.5)/18*500,300-(circleCount[index-2]*w));
  fill(255);
  
  frameRate(30);
  
  // sequence
  for(n=0;n<seq[index];n++) {
    seq.push(index%2+1);
    if(index%2==0) {
      circleCount.push(oneCount);
      oneCount++;
    } else {
      circleCount.push(twoCount);
      twoCount++;
    }
  }
  
  // draw circles
  noStroke();
  for(b=0;b<twoCount;b++) {
    ellipse(gap,b*w,6,6);
  }
  for(c=0;c<oneCount;c++) {
    ellipse(-gap,c*w,6,6);
  }
  
  stroke(255,0,0);
  strokeWeight(2);
  
  // draw lines
  let a = 
    new Lines((seq[index-2]-1.5)*2*gap,
    circleCount[index-2]*w,
    (seq[index-1]-1.5)*2*gap,
    circleCount[index-1]*w);
  
  lines.push(a);
  
  for(let a of lines) {
    a.show();
  }
  
  index++;
}