dragonCurve

let len=10;
let x=0,y=0,x2=10,y2=0;
let strA='R'
let it = 2
let round =0
let sf=1;
function setup() {
  createCanvas(500, 500);
  stroke(0)
  background(0);
  x2=len;
  angleMode(DEGREES)
  strokeWeight(3);
  for(let i=0;i<10;i++){
    iterate()
  }
}
function draw() {
  translate(width/2,width/2);
  scale(0.45,-0.45);
  rotate(60+10*frameCount/200);
  stroke(50,200-50*sin(frameCount),255-200*cos(frameCount));
  drawCurve();
  rotate(180);
  drawCurve();
  stroke(100,200-100*cos(frameCount),255-150*sin(frameCount));
  push();
  rotate(frameCount);
  strokeWeight(2);
  drawCurve();
  pop();
}

function iterate(){
  t = strA.length;
  tmp = strA +'R';
  tmp2='';
  for (let i=t-1;i>=0;i--){
    if (strA.charAt(i)== 'R'){
      tmp = tmp+'L';
    }
    if (strA.charAt(i)== 'L'){
      tmp=tmp+'R';
    }
  }
  strA = tmp;
  it = it+1;
}

function drawCurve(){
  k=int(strA.length);
  line(0,0,len,0)
  x=0;y=0;x2=len;y2=0;
  for (let j=0;j<k;j++){ 
    if ((strA.charAt(j)=='R' && x2>x) ||(strA.charAt(j)=='L' && x2<x) ){
      x3=x2;
      y3=y2-len;
    }
    if ((strA.charAt(j)=='R' && y2>y) ||(strA.charAt(j)=='L' && y2<y) ){
      x3=x2+len;
      y3=y2;
    }
    if ((strA.charAt(j)=='R' && y2<y) ||(strA.charAt(j)=='L' && y2>y) ){
      x3=x2-len;
      y3=y2;
    }
    if ((strA.charAt(j)=='R' && x2<x) ||(strA.charAt(j)=='L' && x<x2) ){
      x3=x2;
      y3=y2+len;
    }
      line(x2,y2,x3,y3);
      x=x2;
      y=y2;
      x2=x3;
      y2=y3;
  }
}