problem with commnunicating arduino with processing (both sending and receiving)

int signal1 = 1;
int signal0 = 0;

void setup()
{
  Serial.begin(9600);
  pinMode(13, OUTPUT);
}

void loop() {
  byte check;
  if (Serial.available()>0) {
    check = Serial.read();
    if(check == 1) {
      digitalWrite(13, HIGH);
      delay(3000); 
      Serial.write(signal1);
    } else { 
    digitalWrite(13, LOW);
    Serial.write(signal0);
    }
  }
}

import processing.opengl.*;
import processing.serial.*;
Serial myPort;

int signal;
Mover[] mover;
int nummover = 7;
  int sta;
  
void setup() {
  frameRate(30);
  size(1000,1000,OPENGL);
  smooth();
  background(0); 
  println(Serial.list());
  myPort = new Serial(this, Serial.list()[0], 9600);
  mover = new Mover[nummover];
  for(int i=0; i<nummover; i++) {
    mover[i]=new Mover();
  }
}

void draw() {
  noStroke();
  background(255);  
  for (int i=0; i<nummover; i++) {
    mover[i].update();
    mover[i].checkedge();
    mover[i].display();
  }

  if(mover[0].putAhold == true) {
    sta = 1;
  } 
  else {
    sta = 3;
  }  
  myPort.write(sta);
  println(sta);
}

void serialEvent(Serial myPort) {
 signal = myPort.read();  
// println(signal);
 if(signal == 1) {
    for (int i=0; i<nummover; i++) {
      mover[i].putAhold = false;
    }
  }  
}

class Mover {
  PVector[] location;
  PVector velocity;
  PVector acc;
  float theta=random(360);
  float ra=6;
  float co=20;
  int tail = 250;
  boolean putAhold = false;

  Mover () {
    location = new PVector[tail];
    for (int i=0; i<tail; i++) { 
      location[i] = new PVector(0,height/2);
    }
    velocity = new PVector(0,0);
  }

  void update() {

    acc = new PVector(ra,cos(radians(theta))*ra);
    acc.normalize();
    velocity.add(acc);
    if(putAhold == true) {
      velocity.limit(0);
    } 
    if(putAhold == false) {
      velocity.limit(6);
    }

    for(int i=tail-2; i>=0; i--) {
      location[i+1].x = location[i].x;
      location[i+1].y = location[i].y;
      location[i].add(velocity);
    }
    theta += 5;
  }

  void checkedge() {
    for(int i=tail-2; i>=0; i--) { 
      if (location[i].x>width) {
        location[i].x=0;
        putAhold = true;
      }
    }
  }

  void display() {
    for(int i=tail-2; i>=0; i--) { 
      strokeWeight(5);
      stroke(0,(100-i*1));
      if(location[i+1].x - location[i].x < 2) {
        line(location[i].x, location[i].y, location[i+1].x, location[i+1].y);
      }
    }
  }
}