class Map
{
 private int[][] mapx;
 private int cols;
 private int rows;

 public Map ()
 {
   cols = 20;
   rows = 20;
   mapx = new int[cols][rows];
   for(int i = 0; i < mapx.length; ++i)
   {
     for (int j = 0; i < mapx.length; ++j)
     {
        mapx[i][j] = (int) random (0, 3) * 100;
     }
   }
 }

 public void Show_Map ()
 {
   for(int i = 0; i < mapx.length; ++i)
   {
     for (int j = 0; i < mapx.length; ++j)
     {
        if (mapx[i][j] == 100)
       {
         fill (255, 0, 0);
         rect (i * 10, j * 10, 10, 10);
       }
        if (mapx[i][j] == 200)
       {
         fill (0, 255, 0);
         rect (i * 10, j * 10, 10, 10);
       }
          if (mapx[i][j] == 300)
       {
         fill (0, 0, 255);
         rect (i * 10, j * 10, 10, 10);
       }
     }
   }
  }
}

Map map1 = new Map ();

void setup ()
{
 size (300, 300, P2D);
}

void draw ()
{
 background (255);
 map1.Show_Map ();
}