gistfile1.java

int width = 200;
int height = 200;

int numsquares = width / 20;


Square[][] squares = new Square[numsquares][numsquares];

void setup() {

  for(int i = 0; i < squares.length; i++) {
    for(int j = 0; j < squares[0].length; j++) {     
      squares[i][j] = new Square();
    }
  }
  
  background(255);
  size(width + 1, height + 1);


}

void draw() {

   for(int i = 0; i < squares.length; i++) {
    for(int j = 0; j < squares[0].length; j++) {
      if(squares[i][j] != null) {
        squares[i][j].display();    
      }
    }
  }
}

class Square {
  
  int x;
  int y;
  color c;
 
 Square() {
  x = (int) random(numsquares);
  y = (int) random(numsquares); 
  c = color(255,0,0);
 } 
 
 void display() {
  fill(c);
  noStroke();
  rect(x * (width / numsquares) + 1, 
    y * (height / numsquares) + 1, 
    width / numsquares - 1, 
    height / numsquares - 1); 
 }
  
  
  
}