// Learning Processing
  // Daniel Shiffman
  // http://www.learningprocessing.com
  
  // Example 13-10: Two-dimensional array of objects
  
  // 2D Array of objects
  Cell[][] grid; 
  
  // Number of columns and rows in the grid
  int cols = 10;
  int rows = 10;
  
  void setup() {
    size(200,200);
    grid = new Cell[cols][rows];
    
    // The counter variables i and j are also the column and row numbers
    // In this example, they are used as arguments to the constructor for each object in the grid.
    for (int i = 0; i < cols; i ++ ) {
      for (int j = 0; j < rows; j ++ ) {
        // Initialize each object
        grid[i][j] = new Cell(i*20,j*20,20,20,i + j);
      }
    }
  }
  
  void draw() {
    background(0);
    for (int i = 0; i < cols; i ++ ) {     
      for (int j = 0; j < rows; j ++ ) {
        // Oscillate and display each object
        grid[i][j].oscillate();
        grid[i][j].display();
      }
    }
  }