//press UP and DOWN to change refreshrate
Pixel[][] pixel;

int cols = 21, rows =21, scala =20;
int cnt=0, size=1;
int yCoor, xCoor;
int refresh, r_size=20;
int[][] coords = new int[8][];


void setup() {

  size(400, 400);
  frameRate(12);
  pixel = new Pixel[cols][rows];
  background(0);
  for (int i = 0; i < cols; i ++ ) {
    for (int j = 0; j < rows; j ++ ) {
      pixel[i][j] = new Pixel(i*scala, j*scala);
    }
  }

  coords[0]=new int[] {1,0};
  coords[1]=new int[] {1,1};
  coords[2]=new int[] {0,1};
  coords[3]=new int[] {-1,1};
  coords[4]=new int[] {-1,0};
  coords[5]=new int[] {-1,-1};
  coords[6]=new int[] {0,-1};
  coords[7]=new int[] {1,-1};

}

void draw() {
  refresh++;
  if (refresh>r_size) {
    background(0);
    refresh=0;
  }

  if (size!=1) {
    cnt++;
    if (cnt>7) {
      int c1 = int(random(1, 7));
      int c2 = int(random(1, 7));
      if(refresh%2==1){
      yCoor+=coords[c1][0];
      xCoor-=coords[c2][0];
      }else{
      yCoor+=coords[c1][0];
      xCoor+=coords[c2][0];
      }
    }
    cnt%=8;
  }
  rotor();
}

void mousePressed() {
  xCoor = mouseX/scala;
  yCoor = mouseY/scala;
  size=8;
}

void rotor() {

  if (size==1) {
  } else if (xCoor>1 && xCoor<cols-1 && yCoor>1 && yCoor<rows-1) {

    translate(-scala, -scala);

    int xPoint=xCoor+coords[cnt][0];
    int yPoint=yCoor+coords[cnt][1];

    pixel[xPoint][yPoint].display();
    pixel[yPoint][xPoint].display();
    pixel[cols-xPoint][rows-yPoint].display();
    pixel[cols-yPoint][rows-xPoint].display();
  } else {
    xCoor=cols/2;
    yCoor=rows/2;
  }
}



class Pixel {

  float x, y;

  Pixel(float _x, float _y) {
    x = _x;
    y = _y;
  }

  void display() {

    fill(255/(1+cnt));
    stroke(0);
    rect(x, y, scala, scala);
  }
}

void keyPressed(){
  if (keyCode== UP && r_size<49) {
    r_size+=1;
    println("RefreshSize of " + r_size);
  }

  if (keyCode== DOWN && r_size>0) {
    r_size-=1;
    println("RefreshSize of " + r_size);
  }
}